Conductive polishing article for electrochemical mechanical polishing

ABSTRACT

Embodiments of a ball assembly are provided. In one embodiment, a ball assembly includes a housing, a ball, a conductive adapter and a contact element. The housing has an annular seat extending into a first end of an interior passage. The conductive adapter is coupled to a second end of the housing. The contact element electrically couples the adapter and the ball with is retained in the housing between seat and the adapter.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of co-pending U.S.patent application Ser. No. 10/608,513, filed Jun. 26, 2003 (hereinafterreferred to as the “'513 application”), which is a continuation-in-partof co-pending U.S. patent application No. 10/140,010, filed May 7, 2002.The '513 application is also a continuation-in-part of co-pending U.S.patent application No. 10/211,626, filed Aug. 2, 2002, which is acontinuation-in-part of co-pending U.S. patent application No.10/033,732, filed Dec. 27, 2001, which is a continuation-in-part of U.S.patent application No. 09/505,899, filed Feb. 17, 2000. The '513application is additionally a continuation-in-part of copending U.S.patent application Ser. No. 10/210,972, filed Aug. 2, 2002, which isalso a continuation-in-part of U.S. patent application No. 09/505,899,filed Feb. 17, 2000. The '513 application is furthercontinuation-in-part of co-pending U.S. patent application No.10/151,538, filed May 16, 2002. This application is also acontinuation-in-part of co-pending U.S. patent application Ser. No.10/244,697, filed Sep. 16, 2002, which is a continuation-in-part of U.S.Application Ser. No. 10/244,688, filed Sep. 16, 2002, and of co-pendingU.S. patent application Ser. No. 10/391,324, filed Mar. 18, 2003. All ofthe above referenced applications are hereby incorporated by referencein their entireties.

[0002] This application is additionally related to U.S. patentapplication Ser. No. 10/033,732, filed on Dec. 27, 2001; U.S. patentapplication Ser. No. 10/455,491, filed Jun. 6, 2003; and U.S. patentapplication Ser. No. 10,455,895, filed Jun. 6, 2003, all of which arealso incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] The present invention relates to an article of manufacture andapparatus for planarizing a substrate surface.

[0005] 2. Background of the Related Art

[0006] Sub-quarter micron multi-level metallization is one of the keytechnologies for the next generation of ultra large-scale integration(ULSI). The multilevel interconnects that lie at the heart of thistechnology require planarization of interconnect features formed in highaspect ratio apertures, including contacts, vias, lines and otherfeatures. Reliable formation of these interconnect features is veryimportant to the success of ULSI and to the continued effort to increasecircuit density and quality on individual substrates and die.

[0007] In the fabrication of integrated circuits and other electronicdevices, multiple layers of conducting, semiconducting, and dielectricmaterials are deposited on or removed from a surface of a substrate.Thin layers of conducting, semiconducting, and dielectric materials maybe deposited by a number of deposition techniques. Common depositiontechniques in modern processing include physical vapor deposition (PVD),also known as sputtering, chemical vapor deposition (CVD),plasma-enhanced chemical vapor deposition (PECVD), and electrochemicalplating (ECP).

[0008] As layers of materials are sequentially deposited and removed,the uppermost surface of the substrate may become non-planar across itssurface and require planarization. Planarizing a surface, or “polishing”a surface, is a process where material is removed from the surface ofthe substrate to form a generally even, planar surface. Planarization isuseful in removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches, and contaminated layers or materials. Planarization is alsouseful in forming features on a substrate by removing excess depositedmaterial used to fill the features and to provide an even surface forsubsequent levels of metallization and processing.

[0009] Chemical mechanical planarization, or chemical mechanicalpolishing (CMP), is a common technique used to planarize substrates. CMPutilizes a chemical composition, typically a slurry or other fluidmedium, for selective removal of material from substrates. Inconventional CMP techniques, a substrate carrier or polishing head ismounted on a carrier assembly and positioned in contact with a polishingpad in a CMP apparatus. The carrier assembly provides a controllablepressure to the substrate urging the substrate against the polishingpad. The pad is moved relative to the substrate by an external drivingforce. The CMP apparatus effects polishing or rubbing movement betweenthe surface of the substrate and the polishing pad while dispersing apolishing composition to effect chemical activity and/or mechanicalactivity and consequential removal of material from the surface of thesubstrate.

[0010] One material increasingly utilized in integrated circuitfabrication is copper due to its desirable electrical properties.However, copper has its own special fabrication problems. For example,copper is difficult to pattern and etch and new processes andtechniques, such as damascene or dual damascene processes, are beingused to form copper substrate features.

[0011] In damascene processes, a feature is defined in a dielectricmaterial and subsequently filled with copper. Dielectric materials withlow dielectric constants, i.e., less than about 3, are being used in themanufacture of copper damascenes. Barrier layer materials are depositedconformally on the surfaces of the features formed in the dielectriclayer prior to deposition of copper material. Copper material is thendeposited over the barrier layer and the surrounding field. However,copper fill of the features usually results in excess copper material,or overburden, on the substrate surface that must be removed to form acopper filled feature in the dielectric material and prepare thesubstrate surface for subsequent processing.

[0012] One challenge that is presented in polishing copper materials isthat the interface between the conductive material and the barrier layeris generally nonplanar and residual copper material is retained inirregularities formed by the nonplanar interface. Further, theconductive material and the barrier materials are often removed from thesubstrate surface at different rates, both of which can result in excessconductive material being retained as residues on the substrate surface.Additionally, the substrate surface may have different surfacetopography, depending on the density or size of features formed therein.Copper material is removed at different removal rates along thedifferent surface topography of the substrate surface, which makeseffective removal of copper material from the substrate surface andfinal planarity of the substrate surface difficult to achieve.

[0013] One solution to remove all of the desired copper material fromthe substrate surface is to overpolish the substrate surface. However,overpolishing of some materials can result in the formation oftopographical defects, such as concavities or depressions in features,referred to as dishing, or excessive removal of dielectric material,referred to as erosion. The topographical defects from dishing anderosion can further lead to non-uniform removal of additional materials,such as barrier layer materials disposed thereunder, and produce asubstrate surface having a less than desirable polishing quality.

[0014] Another problem with the polishing of copper surfaces arises fromthe use of low dielectric constant (low k) dielectric materials to formcopper damascenes in the substrate surface. Low k dielectric materials,such as carbon doped silicon oxides, may deform or fracture underconventional polishing pressures (i.e., about 6 psi), called downforce,which can detrimentally affect substrate polish quality anddetrimentally affect device formation. For example, relative rotationalmovement between the substrate and a polishing pad can induce a shearforce along the substrate surface and deform the low k material to formtopographical defects, which can detrimentally affect subsequentpolishing.

[0015] One solution for polishing copper in low dielectric materials isby polishing copper by electrochemical mechanical polishing (ECMP)techniques. ECMP techniques remove conductive material from a substratesurface by electrochemical dissolution while concurrently polishing thesubstrate with reduced mechanical abrasion compared to conventional CMPprocesses. The electrochemical dissolution is performed by applying abias between a cathode and substrate surface to remove conductivematerials from a substrate surface into a surrounding electrolyte.

[0016] In one embodiment of an ECMP system, the bias is applied by aring of conductive contacts in electrical communication with thesubstrate surface in a substrate support device, such as a substratecarrier head. However, the contact ring has been observed to exhibitnon-uniform distribution of current over the substrate surface, whichresults in non-uniform dissolution, especially during overpolishingwhere a ring of conductive contacts doesn't efficiently remove residues.Mechanical abrasion is performed by contacting the substrate with aconventional polishing pad and providing relative motion between thesubstrate and polishing pad. However, conventional polishing pads oftenlimit electrolyte flow to the surface of the substrate. Additionally,the polishing pad may be composed of insulative materials that mayinterfere with the application of bias to the substrate surface andresult in non-uniform or variable dissolution of material from thesubstrate surface.

[0017] As a result, there is a need for an improved polishing articlefor the removal of conductive material on a substrate surface.

SUMMARY OF THE INVENTION

[0018] Aspects of the invention generally provide an article ofmanufacture and an apparatus for planarizing a layer on a substrateusing electrochemical deposition techniques, electrochemical dissolutiontechniques, polishing techniques, and/or combinations thereof.

[0019] In one aspect, a polishing article for polishing a substrateincludes a body having a surface adapted to polish the substrate and atleast one conductive element embedded at least partially in the body.The conductive element may include fibers coated with a conductivematerial, a conductive filler, or combinations thereof, which may bedisposed in a binder material. The conductive element may include afabric of interwoven fibers coated with the conductive material embeddedat least partially in the body, a composite of fibers coated with theconductive material, conductive fillers, or combinations thereof, and abinder, embedded at least partially in the body, or combinationsthereof. The conductive element may have a contact surface that extendsbeyond a plane defined by the polishing surface and may comprise a coil,one or more loops, one or more strands, an interwoven fabric ofmaterials, or combinations thereof. A plurality of perforations and aplurality of grooves may be formed in the polishing article tofacilitate flow of material through and across the polishing article.

[0020] In another aspect, a polishing article is provided for processinga substrate surface, such as a conductive layer deposited on thesubstrate surface. The polishing article include a body comprising atleast a portion of fibers coated with a conductive material, conductivefillers, or combinations thereof, and adapted to polish the substrate. Aplurality of perforations and a plurality of grooves may be formed inthe polishing article to facilitate flow of material through and aroundthe polishing article.

[0021] In another aspect, the polishing articles may be disposed in anapparatus for processing a substrate including a basin, a permeable discdisposed in the basin, the polishing article or the article ofmanufacture disposed on the permeable disk, an electrode disposed in thebasin between the permeable disc and the bottom of the basin, and apolishing head adapted to retain the substrate during processing.

[0022] In another aspect, the polishing articles may be used as aconductive polishing article in a method for processing a substrateincluding providing an apparatus containing an enclosure, disposing aconductive polishing article in the enclosure, supplying an electricallyconductive solution to the enclosure at a flow rate up to about 20gallons per minute (GPM), positioning the substrate adjacent theconductive polishing article in the electrically conductive solution,contacting a surface of the substrate with the conductive polishingarticle in the electrically conductive solution, applying a bias betweenan electrode and the conductive polishing article, and removing at leasta portion of the surface of the substrate surface.

[0023] In another embodiment of the invention, a polishing article forprocessing a substrate comprises a fabric layer having a conductivelayer disposed thereover. The conductive layer has an exposed surfaceadapted to polish a substrate. The fabric layer may be woven ornon-woven. The conductive layer may be comprised of a soft conductivematerial and, in one embodiment, the exposed surface may be planar orembossed.

[0024] In another embodiment of the invention, a polishing article forprocessing a substrate comprises a conductive fabric layer having aconductive layer disposed thereover. The conductive layer has an exposedsurface adapted to polish a substrate. The conductive fabric layer maybe woven or non-woven. The conductive layer may be comprised of a softconductive material and, in one embodiment, the exposed surface may beplanar or embossed.

[0025] In another embodiment of the invention, a polishing article forprocessing a substrate comprises a conductive fabric layer having anonconductive layer disposed thereover. The nonconductive layer has anexposed surface adapted to polish a substrate with at least partiallyexposed conductive fabric to positively bias polishing substrate. Theconductive fabric layer may be woven or non-woven. The nonconductivelayer may be comprised of an abrasive material and, in one embodiment,the exposed surface may be planar or embossed.

[0026] In another embodiment of the invention, a polishing article forprocessing a substrate comprises a conductive portion having abrasiveelements extending therefrom. In another embodiment of the invention, apolishing article for processing a substrate comprises conductiveportion having conductive rollers extending therefrom. In oneembodiment, the conductive rollers have a polymer core at leastpartially covered by a conductive coating that is comprised of a softconductive material.

[0027] In another aspect, a ball assembly is provided. In oneembodiment, the ball assembly includes a housing, a ball, a conductiveadapter and a contact element. The housing has an annular seat extendinginto a first end of an interior passage. The conductive adapter iscoupled to a second end of the housing. The contact element electricallycouples the adapter and the ball with is retained in the housing betweenseat and the adapter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] So that the manner in which the above recited aspects of theinvention are attained and can be understood in detail, a moreparticular description of the invention, briefly summarized above, maybe had by reference to embodiments thereof which are illustrated in theappended drawings.

[0029] It is to be noted, however, that the appended drawings illustrateonly typical embodiments of this invention and, therefore, are not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

[0030]FIG. 1 is a plan view of one embodiment of a processing apparatusof the invention;

[0031]FIG. 2 is a sectional view of one embodiment of an ECMP station;

[0032]FIG. 3 is a partial cross-sectional view of one embodiment of apolishing article;

[0033]FIG. 4 is a top plan view of one embodiment of a grooved polishingarticle;

[0034] FIGS. 5-6 are top plan views of embodiments of a groovedpolishing article;

[0035]FIG. 7A is a top view of a conductive cloth or fabric describedherein;

[0036]FIGS. 7B and 7C are partial cross-sectional views of polishingarticles having a polishing surface comprising a conductive cloth orfabric;

[0037]FIG. 7D is a partial cross-sectional view of one embodiment of apolishing article including a metal foil;

[0038]FIG. 7E is another embodiment of a polish article comprising afabric material;

[0039]FIG. 7F is another embodiment of a polish article having a windowformed therein;

[0040]FIGS. 8A and 8B are top and cross-section schematic views,respectively, of one embodiment of a polishing article having aconductive element;

[0041]FIGS. 8C and 8D are top and cross-section schematic views,respectively, of one embodiment of a polishing article having aconductive element;

[0042]FIGS. 9A and 9B are perspective views of other embodiments of apolishing article having a conductive element;

[0043]FIG. 10A is a partial perspective view of another embodiment of apolishing article;

[0044]FIG. 10B is a partial perspective view of another embodiment of apolishing article;

[0045]FIG. 10C is a partial perspective view of another embodiment of apolishing article;

[0046]FIG. 10D is a partial perspective view of another embodiment of apolishing article;

[0047]FIG. 10E is a partial perspective view of another embodiment of apolishing article;

[0048] FIGS. 11A-11C are schematic side views of one embodiment of asubstrate contacting one embodiment of a polishing article describedherein;

[0049] FIGS. 12A-12D are top and side schematic views of embodiments ofa polishing article having extensions connected to a power source;

[0050]FIGS. 12E and 12F show side schematic and exploded perspectiveviews of another embodiment of providing power to a polishing article;

[0051] FIGS. 13A-B are top and sectional views of another embodiment ofa conductive article;

[0052] FIGS. 14A-D are top and sectional views of another embodiment ofa conductive article;

[0053] FIGS. 15-17 are a sectional view of alternate embodiments of aconductive article;

[0054]FIG. 18 is sectional view of another embodiment of a conductivearticle having one embodiment of a ball assembly; and

[0055] FIGS. 19A-B are side and exploded views of the ball assembly ofFIG. 18;

[0056]FIG. 20 is one embodiment of a contact element of the ballassembly of FIGS. 18 and 19A-B;

[0057] FIGS. 21-23 are perspective and sectional views of anotherembodiment of a conductive article having another embodiment of a ballassembly; and

[0058] FIGS. 24A-B are bottom views of alternate embodiments of anelectrode that may advantageously adapted for use with differentembodiments of conductive articles.

[0059] To facilitate understanding, identical reference numerals havebeen used, wherever possible, to designate identical elements that arecommon to the figures.

DETAILED DESCRIPTION

[0060] The words and phrases used herein should be given their ordinaryand customary meaning in the art by one skilled in the art unlessotherwise further defined. Chemical-mechanical polishing should bebroadly construed and includes, but is not limited to, abrading asubstrate surface by chemical activity, mechanical activity, or acombination of both chemical and mechanical activity. Electropolishingshould be broadly construed and includes, but is not limited to,planarizing a substrate by the application of electrochemical activity,such as by anodic dissolution.

[0061] Electrochemical mechanical polishing (ECMP) should be broadlyconstrued and includes, but is not limited to, planarizing a substrateby the application of electrochemical activity, chemical activity,mechanical activity, or a combination of electrochemical, chemical, andmechanical activity to remove material from a substrate surface.

[0062] Electrochemical mechanical plating process (ECMPP) should bebroadly construed and includes, but is not limited to, electrochemicallydepositing material on a substrate and generally planarizing thedeposited material by the application of electrochemical activity,chemical activity, mechanical activity, or a combination ofelectrochemical, chemical, and mechanical activity.

[0063] Anodic dissolution should be broadly construed and includes, butis not limited to, the application of an anodic bias to a substratedirectly or indirectly which results in the removal of conductivematerial from a substrate surface and into a surrounding electrolytesolution. Polishing surface is broadly defined as the portion of anarticle of manufacture that at least partially contacts a substratesurface during processing or electrically couples an article ofmanufacture to a substrate surface either directly through contact orindirectly through an electrically conductive medium.

[0064] Polishing Apparatus

[0065]FIG. 1 depicts a processing apparatus 100 having at least onestation suitable for electrochemical deposition and chemical mechanicalpolishing, such as electrochemical mechanical polishing (ECMP) station102 and at least one conventional polishing or buffing station 106disposed on a single platform or tool. One polishing tool that may beadapted to benefit from the invention is a MIRRA® Mesa™ chemicalmechanical polisher available from Applied Materials, Inc. located inSanta Clara, Calif.

[0066] For example, in the apparatus 100 shown in FIG. 1, the apparatus100 includes two ECMP stations 102 and one polishing station 106. Thestations may be used for processing a substrate surface. For example, asubstrate having feature definitions formed therein and filled with abarrier layer and then a conductive material disposed over the barrierlayer may have the conducive material removed in two steps in the twoECMP stations 102 with the barrier layer polished in the polishingstation 106 to form a planarized surface.

[0067] The exemplary apparatus 100 generally includes a base 108 thatsupports one or more ECMP stations 102, one or more polishing stations106, a transfer station 110 and a carousel 112. The transfer station 110generally facilitates transfer of substrates 114 to and from theapparatus 100 via a loading robot 116. The loading robot 116 typicallytransfers substrates 114 between the transfer station 110 and a factoryinterface 120 that may include a cleaning module 122, a metrology device104 and one or more substrate storage cassettes 118. One example of ametrology device 104 is a NovaScan™ Integrated Thickness Monitoringsystem, available from Nova Measuring Instruments, Inc., located inPhoenix, Ariz.

[0068] Alternatively, the loading robot 116 (or factory interface 120)may transfer substrates to one or more other processing tools (notshown) such as a chemical vapor deposition tool, physical vapordeposition tool, etch tool and the like.

[0069] In one embodiment, the transfer station 110 comprises at least aninput buffer station 124, an output buffer station 126, a transfer robot132, and a load cup assembly 128. The loading robot 116 places thesubstrate 114 onto the input buffer station 124. The transfer robot 132has two gripper assemblies, each having pneumatic gripper fingers thathold the substrate 114 by the substrate's edge. The transfer robot 132lifts the substrate 114 from the input buffer station 124 and rotatesthe gripper and substrate 114 to position the substrate 114 over theload cup assembly 128, then places the substrate 114 down onto the loadcup assembly 128.

[0070] The carousel 112 generally supports a plurality of polishingheads 130, each of which retains one substrate 114 during processing.The carousel 112 transfers the polishing heads 130 between the transferstation 110, the one or more ECMP stations 102 and the one or morepolishing stations 106. One carousel 112 that may be adapted to benefitfrom the invention is generally described in U.S Pat. No. 5,804,507,issued Sep. 8, 1998 to Tolles et al., which is hereby incorporated byreference in its entirety.

[0071] Generally, the carousel 112 is centrally disposed on the base108. The carousel 112 typically includes a plurality of arms 138. Eacharm 138 generally supports one of the polishing heads 130. One of thearms 138 depicted in FIG. 1 is not shown so that the transfer station110 may be seen. The carousel 112 is indexable such that the polishinghead 130 may be moved between the stations 102, 106 and the transferstation 110 in a sequence defined by the user.

[0072] Generally the polishing head 130 retains the substrate 114 whilethe substrate 114 is disposed in the ECMP station 102 or polishingstation 106. The arrangement of the ECMP stations 106 and polishingstations 102 on the apparatus 100 allow for the substrate 114 to besequentially plated or polished by moving the substrate between stationswhile being retained in the same polishing head 130. One polishing headthat may be adapted to the invention is a TITAN HEAD™ substrate carrier,manufactured by Applied Materials, Inc., located in Santa Clara, Calif.

[0073] Examples of embodiments of polishing heads 130 that may be usedwith the polishing apparatus 100 described herein are described in U.S.Pat. No. 6,183,354, issued Feb. 6, 2001 to Zuniga, et al., which ishereby incorporated by reference in its entirety.

[0074] To facilitate control of the polishing apparatus 100 andprocesses performed thereon, a controller 140 comprising a centralprocessing unit (CPU) 142, memory 144, and support circuits 146, isconnected to the polishing apparatus 100. The CPU 142 may be one of anyform of computer processor that can be used in an industrial setting forcontrolling various drives and pressures. The memory 144 is connected tothe CPU 142. The memory 144, or computer-readable medium, may be one ormore of readily available memory such as random access memory (RAM),read only memory (ROM), floppy disk, hard disk, or any other form ofdigital storage, local or remote. The support circuits 146 are connectedto the CPU 142 for supporting the processor in a conventional manner.These circuits include cache, power supplies, clock circuits,input/output circuitry, subsystems, and the like.

[0075] Power to operate the polishing apparatus 100 and/or thecontroller 140 is provided by a power supply 150. Illustratively, thepower supply 150 is shown connected to multiple components of thepolishing apparatus 100, including the transfer station 110, the factoryinterface 120, the loading robot 116 and the controller 140. In otherembodiments separate power supplies are provided for two or morecomponents of the polishing apparatus 100.

[0076]FIG. 2 depicts a sectional view of the polishing head 130supported above an ECMP station 102. The ECMP station 102 generallyincludes a basin 202, an electrode 204, polishing article 205, a disc206 and a cover 208. In one embodiment, the basin 202 is coupled to thebase 108 of the polishing apparatus 100. The basin 202 generally definesa container or electrolyte cell in which a conductive fluid such as anelectrolyte 220 can be confined. The electrolyte 220 used in processingthe substrate 114 can be used to process metals such as copper,aluminum, tungsten, gold, silver, or any other materials that can beelectrochemically deposited onto or electrochemically removed from thesubstrate 114.

[0077] The basin 202 can be a bowl shaped member made of a plastic suchas fluoropolymers, polytetrafluoroethylene, PFA, PE, PES, or othermaterials that are compatible with electroplating and electropolishingchemistries. The basin 202 has a bottom 210 that includes an aperture216 and a drain 214. The aperture 216 is generally disposed in thecenter of the bottom 210 and allows a shaft 212 to pass therethrough. Aseal 218 is disposed between the aperture 216 and the shaft 212 andallows the shaft 212 to rotate while preventing fluids disposed in thebasin 202 from passing through the aperture 216.

[0078] The basin 202 typically includes the electrode 204, the disc 206,and the polishing article 205 disposed therein. Polishing article 205,such as a polishing pad, is disposed and supported in the basin 202 onthe disc 206.

[0079] The electrode 204 is a counter-electrode to the substrate 114and/or polishing article 205 contacting a substrate surface. Thepolishing article 205 is at least partially conductive and may act as anelectrode in combination with the substrate during electrochemicalprocesses, such as an electrochemical mechanical plating process(ECMPP), which includes electrochemical deposition and chemicalmechanical polishing, or electrochemical dissolution. The electrode 204may be an anode or cathode depending upon the positive bias (anode) ornegative bias (cathode) applied between the electrode 204 and polishingarticle 405.

[0080] For example, depositing material from an electrolyte on thesubstrate surface, the electrode 204 acts as an anode and the substratesurface and/or polishing article 205 acts as a cathode. When removingmaterial from a substrate surface, such as by dissolution from anapplied bias, the electrode 204 functions as a cathode and the substratesurface and/or polishing article 205 may act as an anode for thedissolution process.

[0081] The electrode 204 is generally positioned between the disc 206and the bottom 210 of the basin 202 where it may be immersed in orexposed to the electrolyte 220. The electrode 204 may be fabricated froma magnetically coupleable material to allow for the electrode to besecured to the platen. The electrode 204 can be a plate-like member, aplate having multiple apertures formed therethrough, or a plurality ofelectrode pieces disposed in a permeable membrane or container. Apermeable membrane (not shown) may be disposed between the disc 206 andthe electrode 204 or electrode 204 and polishing article 205 to filterbubbles, such as hydrogen bubbles, form the wafer surface and to reducedefect formation and stabilize or more uniformly apply current or powertherebetween.

[0082] For electrodeposition processes, the electrode 204 is made of thematerial to be deposited or removed, such as copper, aluminum, gold,silver, tungsten and other materials which can be electrochemicallydeposited on the substrate 114. For electrochemical removal processes,such as anodic dissolution, the electrode 204 may include anon-consumable electrode of a material other than the depositedmaterial, for example, platinum, carbon, or aluminum, for copperdissolution.

[0083] The polishing article 205 can be a pad, a web or a belt ofmaterial, which is compatible with the fluid environment and theprocessing specifications. In the embodiment depicted in FIG. 2, thepolishing article 205 is circular in form and positioned at an upper endof the basin 202, supported on its lower surface by the disc 206. Thepolishing article 205 includes at least a partially conductive surfaceof a conductive material, such as one or more conductive elements, forcontact with the substrate surface during processing. The polishingarticle 205 may be a portion or all of a conductive polishing materialor a composite of a conductive polishing material embedded in ordisposed on a conventional polishing material. For example theconductive material may be disposed on a “backing” material disposedbetween the disc 206 and polishing article 205 to tailor the complianceand/or durometer of the polishing article 205 during processing.

[0084] The basin 202, the cover 208, and the disc 206 may be movablydisposed on the base 108. The basin 202, cover 208 and disc 206 may beaxially moved toward the base 108 to facilitate clearance of thepolishing head 130 as the carousel 112 indexes the substrate 114 betweenthe ECMP and polishing stations 102, 106. The disc 206 is disposed inthe basin 202 and coupled to the shaft 212. The shaft 212 is generallycoupled to a motor 224 disposed below the base 108. The motor 224, inresponse to a signal from the controller 140, rotates the disc 206 at apredetermined rate.

[0085] The disc 206 may be a perforated article support made from amaterial compatible with the electrolyte 220 which would notdetrimentally affect polishing. The disc 206 may be fabricated from apolymer, for example fluoropolymers, PE, polytetrafluoroethylene, PFA,PES, HDPE, UHMW or the like. The disc 206 can be secured in the basin202 using fasteners such as screws or other means such as snap orinterference fit with the enclosure, being suspended therein and thelike. The disc 206 is preferably spaced from the electrode 204 toprovide a wider process window, thus reducing the sensitivity ofdepositing material and removing material from the substrate surface tothe electrode 204 dimensions.

[0086] The disc 206 is generally permeable to the electrolyte 220. Inone embodiment, the disc 206 includes a plurality of perforations orchannels 222 formed therein. Perforations include apertures, holes,openings, or passages formed partially or completely through an object,such as the polishing article. The perforation size and density isselected to provide uniform distribution of the electrolyte 220 throughthe disc 206 to the substrate 114.

[0087] In one aspect of the disc 206 includes perforations having adiameter between about 0.02 inches (0.5 millimeters) and about 0.4inches (10 mm). The perforations may have a perforation density betweenabout 20% and about 80% of the polishing article. A perforation densityof about 50% has been observed to provide electrolyte flow with minimaldetrimental effects to polishing processes. Generally, the perforationsof the disc 206 and the polishing article 205 are aligned to provide forsufficient mass flow of electrolyte through the disc 206 and polishingarticle 205 to the substrate surface. The polishing article 205 may bedisposed on the disc 206 by a mechanical clamp or conductive adhesive.

[0088] While the polishing articles described herein forelectrochemical-mechanical polishing (ECMP) processes, the inventioncontemplates using the conductive polishing article in other fabricationprocesses involving electrochemical activity. Examples of such processesusing electrochemical activity include electrochemical deposition, whichinvolves the polishing article 205 being used to apply an uniform biasto a substrate surface for depositing a conductive material without theuse of conventional bias application apparatus, such as edge contacts,and electrochemical mechanical plating processes (ECMPP) that include acombination of electrochemical deposition and chemical mechanicalpolishing.

[0089] In operation, the polishing article 205 is disposed on the disc206 in an electrolyte in the basin 202. A substrate 114 on the polishinghead is disposed in the electrolyte and contacted with the polishingarticle 205. Electrolyte is flowed through the perforations of the disc206 and the polishing article 205 and is distributed on the substratesurface by grooves formed therein. Power from a power source is thenapplied to the conductive polishing article 205 and the electrode 204,and conductive material, such as copper, in the electrolyte is thenremoved by an anodic dissolution method.

[0090] The electrolyte 220 is flowed from a reservoir 233 into thevolume 232 via a nozzle 270. The electrolyte 220 is prevented fromoverflowing the volume 232 by a plurality of holes 234 disposed in askirt 254. The holes 234 generally provide a path through the cover 208for the electrolyte 220 exiting the volume 232 and flowing into thelower portion of the basin 202. At least a portion of the holes 234 aregenerally positioned between a lower surface 236 of the depression 258and the center portion 252. As the holes 234 are typically higher thanthe lower surface 236 of the depression 258, the electrolyte 220 fillsthe volume 232 and is thus brought into contact with the substrate 114and polishing medium 205. Thus, the substrate 114 maintains contact withthe electrolyte 220 through the complete range of relative spacingbetween the cover 208 and the disc 206.

[0091] The electrolyte 220 collected in the basin 202 generally flowsthrough the drain 214 disposed at the bottom 210 into the fluid deliverysystem 272. The fluid delivery system 272 typically includes thereservoir 233 and a pump 242. The electrolyte 220 flowing into the fluiddelivery system 272 is collected in the reservoir 233. The pump 242transfers the electrolyte 220 from the reservoir 233 through a supplyline 244 to the nozzle 270 where the electrolyte 220 recycled throughthe ECMP station 102. A filter 240 is generally disposed between thereservoir 233 and the nozzle 270 to remove particles and agglomeratedmaterial that may be present in the electrolyte 220.

[0092] Electrolyte solutions may include commercially availableelectrolytes. For example, in copper containing material removal, theelectrolyte may include sulfuric acid based electrolytes or phosphoricacid based electrolytes, such as potassium phosphate (K₃PO₄), orcombinations thereof. The electrolyte may also contain derivatives ofsulfuric acid based electrolytes, such as copper sulfate, andderivatives of phosphoric acid based electrolytes, such as copperphosphate. Electrolytes having perchloric acid-acetic acid solutions andderivatives thereof may also be used.

[0093] Additionally, the invention contemplates using electrolytecompositions conventionally used in electroplating or electropolishingprocesses, including conventionally used electroplating orelectropolishing additives, such as brighteners among others. One sourcefor electrolyte solutions used for electrochemical processes such ascopper plating, copper anodic dissolution, or combinations thereof isShipley Leonel, a division of Rohm and Haas, headquartered inPhiladelphia, Pa., under the tradename Ultrafill 2000. An example of asuitable electrolyte composition is described in U.S. patent applicationSer. No. 10/038,066, filed on Jan. 3, 2002, which is incorporated byreference in its entirety.

[0094] Electrolyte solutions are provided to the electrochemical cell toprovide a dynamic flow rate on the substrate surface or between thesubstrate surface and an electrode at a flow rate up to about 20 gallonsper minute (GPM), such as between about 0.5 GPM and about 20 GPM, forexample, at about 2 GPM. It is believed that such flow rates ofelectrolyte evacuate polishing material and chemical by-products fromthe substrate surface and allow refreshing of electrolyte material forimproved polishing rates.

[0095] When using mechanical abrasion in the polishing process, thesubstrate 114 and polishing article 205 are rotated relative to oneanother to remove material from the substrate surface. Mechanicalabrasion may be provided by physical contact with both conductivepolishing materials and conventional polishing materials as describedherein. The substrate 114 and the polishing article 205 are respectivelyrotated at about 5 rpms or greater, such as between about 10 rpms andabout 50 rpms.

[0096] In one embodiment, a high rotational speed polishing process maybe used. The high rotational speed process includes rotating thepolishing article 205 at a platen speed of about 150 rpm or greater,such as between about 150 rpm and about 750 rpm; and the substrate 114may be rotated at a rotational speed between about 150 rpm and about 500rpm, such as between about 300 rpm and about 500 rpm. Furtherdescription of a high rotational speed polishing process that may beused with the polishing articles, processes, and apparatus describedherein is disclosed in U.S. Patent Application Serial No. 60/308,030,filed on Jul. 25, 2001, and entitled, “Method And Apparatus For ChemicalMechanical Polishing Of Semiconductor Substrates.” Other motion,including orbital motion or a sweeping motion across the substratesurface, may also be performed during the process.

[0097] When contacting the substrate surface, a pressure of about 6 psior less, such as about 2 psi or less is applied between the polishingarticle 205 and the substrate surface. If a substrate containing lowdielectric constant material is being polished, a pressure between ofabout 2 psi or less, such as about 0.5 psi or less is used to press thesubstrate 114 against the polishing article 205 during polishing of thesubstrate. In one aspect, a pressure between about 0.1 psi and about 0.2psi may be used to polishing substrates with conductive polishingarticles as described herein.

[0098] In anodic dissolution, a potential difference or bias is appliedbetween the electrode 204, performing as a cathode, and the polishingsurface 310 (See, FIG. 3) of the polishing article 205, performing asthe anode. The substrate in contact with the polishing article ispolarized via the conductive polishing surface article 310 at the sametime the bias is applied to the conductive article support member. Theapplication of the bias allows removal of conductive material, such ascopper-containing materials, formed on a substrate surface. Establishingthe bias may include the application of a voltage of about 15 volts orless to the substrate surface. A voltage between about 0.1 volts andabout 10 volts may be used to dissolve copper-containing material fromthe substrate surface and into the electrolyte. The bias may alsoproduce a current density between about 0.1 milliamps/cm² and about 50milliamps/cm², or between about 0.1 amps to about 20 amps for a 200 mmsubstrate.

[0099] The signal provided by the power supply 150 to establish thepotential difference and perform the anodic dissolution process may bevaried depending upon the requirements for removing material from thesubstrate surface. For example, a time varying anodic signal may beprovided to the conductive polishing medium 205. The signal may also beapplied by electrical pulse modulation techniques. The electrical pulsemodification technique comprises applying a constant current density orvoltage over the substrate for a first time period, then applying aconstant reverse voltage or stopping applying a voltage over thesubstrate for a second time period, and repeating the first and secondsteps. For example, the electrical pulse modification technique may usea varying potential from between about −0.1 volts and about −15 volts tobetween about 0.1 volts and about 15 volts.

[0100] With the correct perforation pattern and density on the polishingmedia, it is believed that biasing the substrate from the polishingarticle 205 provides uniform dissolution of conductive materials, suchas metals, into the electrolyte from the substrate surface as comparedto the higher edge removal rate and lower center removal rate fromconventional edge contact-pins bias.

[0101] Conductive material, such as copper containing material can beremoved from at least a portion of the substrate surface at a rate ofabout 15,000 Å/min or less, such as between about 100 Å/min and about15,000 Å/min. In one embodiment of the invention where the coppermaterial to be removed is about 12,000 Å thick, the voltage may beapplied to the conductive polishing article 205 to provide a removalrate between about 100 Å/min and about 8,000 Å/min.

[0102] Following the electropolishing process, the substrate may befurther polished or buffed to remove barrier layer materials, removesurface defects from dielectric materials, or improve planarity of thepolishing process using the conductive polishing article. An example ofa suitable buffing process and composition is disclosed in co-pendingU.S. patent application Ser. No. 09/569,968, filed on May 11, 2000, andincorporated herein by reference in its entirety.

[0103] Polishing Article Materials

[0104] The polishing articles described herein may be formed fromconductive materials that may comprise a conductive polishing materialor may comprise a conductive element disposed in a dielectric orconductive polishing material. In one embodiment, a conductive polishingmaterial may include conductive fibers, conductive fillers, orcombinations thereof. The conductive fibers, conductive fillers, orcombinations thereof may be dispersed in a polymeric material.

[0105] The conductive fibers may comprise conductive or dielectricmaterials, such as dielectric or conductive polymers or carbon-basedmaterials, at least partially coated or covered with a conductivematerial including a metal, a carbon-based material, a conductiveceramic material, a conductive alloy, or combinations thereof. Theconductive fibers may be in the form of fibers or filaments, aconductive fabric or cloth, one or more loops, coils, or rings ofconductive fibers. Multiple layers of conductive materials, for example,multiple layers of conductive cloth or fabric, may be used to form theconductive polishing material.

[0106] The conductive fibers include dielectric or conductive fibermaterials coated with a conductive material. Dielectric polymericmaterials may be used as fiber materials. Examples of suitabledielectric fiber materials include polymeric materials, such aspolyamides, polyimides, nylon polymer, polyurethane, polyester,polypropylene, polyethylene, polystyrene, polycarbonate, dienecontaining polymers, such as AES (polyacrylontrile ethylene styrene),acrylic polymers, or combinations thereof. The invention alsocontemplates the use of organic or inorganic materials that may be usedas fibers described herein.

[0107] The conductive fiber material may comprise intrinsicallyconductive polymeric materials including polyacetylene,polyethylenedioxythiophene (PEDT), which is commercially available underthe trade name Baytron™, polyaniline, polypyrrole, polythiophene,carbon-based fibers, or combinations thereof. Another example of aconductive polymer is polymer-noble metal hybrid materials.Polymer-noble metal hybrid materials are generally chemically inert witha surrounding electrolyte, such as those with noble metals that areresistant to oxidation. An example of a polymer-noble metal hybridmaterial is a platinum-polymer hybrid material. Examples of conductivepolishing materials, including conductive fibers, are more fullydescribed in co-pending U.S. patent application Ser. No. 10/033,732,filed on Dec. 27, 2001, entitled, “Conductive Polishing Article ForElectrochemical Mechanical Polishing”, which is incorporated herein byreference in its entirety. The invention also contemplates the use oforganic or inorganic materials that may be used as fibers describedherein.

[0108] The fiber material may be solid or hollow in nature. The fiberlength is in the range between about 1 μm and about 1000 mm with adiameter between about 0.1 μm and about 1 mm. In one aspect, thediameter of fiber may be between about 5 μm to about 200 μm with anaspect ratio of length to diameter of about 5 or greater, such as about10 or greater, for conductive polymer composites and foams, such asconductive fibers disposed in polyurethane. The cross-sectional area ofthe fiber may be circular, elliptical, star-patterned, “snow flaked”, orof any other shape of manufactured dielectric or conductive fibers. Highaspect ratio fibers having a length between about 5 mm and about 1000 mmin length and between about 5 μm and about 1000 μm in diameter may beused for forming meshes, loops, fabrics or cloths, of the conductivefibers. The fibers may also have an elasticity modulus in the rangebetween about 10⁴ psi and about 10⁸ psi. However, the inventioncontemplates any elastic modulus necessary to provide for compliant,elastic fibers in the polishing articles and processes described herein.

[0109] Conductive material disposed on the conductive or dielectricfiber material generally include conductive inorganic compounds, such asa metal, a metal alloy, a carbon-based material, a conductive ceramicmaterial, a metal inorganic compound, or combinations thereof. Examplesof metal that may be used for the conductive material coatings hereininclude noble metals, tin, lead, copper, nickel, cobalt, andcombinations thereof. Noble metals include gold, platinum, palladium,iridium, rhenium, rhodium, rhenium, ruthenium, osmium, and combinationsthereof, of which gold and platinum are preferred. The invention alsocontemplates the use of other metals for the conductive materialcoatings than those illustrated herein. Carbon-based material includescarbon black, graphite, and carbon particles capable of being affixed tothe fiber surface. Examples of ceramic materials include niobium carbide(NbC), zirconium carbide (ZrC), tantalum carbide (TaC), titanium carbide(TiC), tungsten carbide (WC), and combinations thereof. The inventionalso contemplates the use of other metals, other carbon-based materials,and other ceramic materials for the conductive material coatings thanthose illustrated herein. Metal inorganic compounds include, forexample, copper sulfide or danjenite, Cu₉S₅, disposed on polymericfibers, such as acrylic or nylon fibers. The danjenite coated fibers arecommercially available under the tradename Thunderon® from Nihon SanmoDyeing Co., Ltd, of Japan. The Thunderon® fibers typically have acoating of danjenite, CU₉S₅, between about 0.03 μm and about 0.1 μm andhave been observed to have conductivities of about 40 Ω/cm. Theconductive coating may be disposed directly on the fiber by plating,coating, physical vapor deposition, chemical deposition, binding, orbonding of the conductive materials. Additionally, a nucleation, orseed, layer of a conductive material, for example, copper, cobalt ornickel, may be used to improve adhesion between the conductive materialand the fiber material. The conductive material may be disposed onindividual dielectric or conductive fibers of variable lengths as wellas on shaped loops, foams, and cloths or fabrics made out of thedielectric or conductive fiber material.

[0110] An example of a suitable conductive fiber is a polyethylene fibercoated with gold. Additional examples of the conductive fibers includeacrylic fibers plated with gold and nylon fibers coated with rhodium. Anexample of a conductive fiber using a nucleation material is a nylonfiber coated with a copper seed layer and a gold layer disposed on thecopper layer.

[0111] The conductive fillers may include carbon based materials orconductive particles and fibers. Examples of conductive carbon-basedmaterials include carbon powder, carbon fibers, carbon nanotubes, carbonnanofoam, carbon aerogels, graphite, and combinations thereof. Examplesof conductive particles or fibers include intrinsically conductivepolymers, dielectric or conductive particles coated with a conductivematerial, dielectric filler materials coated in conductive materials,conductive inorganic particles including metal particles such as gold,platinum, tin, lead and other metal or metal alloy particles, conductiveceramic particle, and combinations thereof. The conductive fillers maybe partially or completely coated with a metal, such as a noble metal, acarbon-based material, conductive ceramic material, a metal inorganiccompound, or combinations thereof, as described herein. An example of afiller material is a carbon fiber or graphite coated with copper ornickel. Conductive fillers may be spherical, elliptical, longitudinalwith certain aspect ratio, such as 2 or greater, or of any other shapeof manufactured fillers. Filler materials are broadly defined herein asmaterials that may be disposed in a second material to alter, thephysical, chemical, or electrical properties of the second material. Assuch, filler materials may also include dielectric or conductive fibermaterial partially or completely coated in a conductive metal orconductive polymers as described herein. The fillers of dielectric orconductive fiber material partially or completely coated in a conductivemetal or conductive polymers may also be complete fibers or pieces offibers.

[0112] The conductive materials are used to coat both dielectric andconductive fibers and fillers to provide a desired level of conductivityfor forming the conductive polishing material. Generally, the coating ofconductive material is deposited on the fiber and/or filler material toa thickness between about 0.01 μm and about 50 μm, such as between about0.02 μm and about 10 μm. The coating typically results in fibers orfillers having resistivities less than about 100 Ω-cm, such as betweenabout 0.001 Ω-cm and about 32 Ω-cm. The invention contemplates thatresistivities are dependent on the materials of both the fiber or fillerand the coating used, and may exhibit resistivities of the conductivematerial coating, for example, platinum, which has a resistivity 9.81μΩ-cm at 0° C. An example of a suitable conductive fiber includes anylon fiber coated with about 0.1 μm copper, nickel, or cobalt, andabout 2 μm of gold disposed on the copper, nickel, or cobalt layer, witha total diameter of the fiber between about 30 μm and about 90 μm.

[0113] The conductive polishing material may include a combination ofthe conductive or dielectric fibers material at least partially coatedor covered with an additional conductive material and conductive fillersfor achieving a desired electrical conductivity or other polishingarticle properties. An example of a combination is the used of goldcoated nylon fibers and graphite as the conductive material comprisingat least a portion of a conductive polishing material.

[0114] The conductive fiber material, the conductive filler material, orcombinations thereof, may be dispersed in a binder material or form acomposite conductive polishing material. One form of binder material isa conventional polishing material. Conventional polishing materials aregenerally dielectric materials such as dielectric polymeric materials.Examples of dielectric polymeric polishing materials includepolyurethane and polyurethane mixed with fillers, polycarbonate,polyphenylene sulfide (PPS), polytetrafluoroethylene polymers,polystyrene, ethylene-propylene-diene-methylene (EPDM), or combinationsthereof, and other polishing materials used in polishing substratesurfaces. The conventional polishing material may also include feltfibers impregnated in urethane or be in a foamed state. The inventioncontemplates that any conventional polishing material may be used as abinder material (also known as a matrix) with the conductive fibers andfillers described herein.

[0115] Additives may be added to the binder material to assist thedispersion of conductive fibers, conductive fillers or combinationsthereof, in the polymer materials. Additives may be used to improve themechanical, thermal, and electrical properties of the polishing materialformed from the fibers and/or fillers and the binder material. Additivesinclude cross-linkers for improving polymer cross-linking anddispersants for dispersing conductive fibers or conductive fillers moreuniformly in the binder material. Examples of cross-linkers includeamino compounds, silane crosslinkers, polyisocyanate compounds, andcombinations thereof. Examples of dispersants include N-substitutedlong-chain alkenyl succinimides, amine salts of high-molecular-weightorganic acids, co-polymers of methacrylic or acrylic acid derivativescontaining polar groups such as amines, amides, imines, imides,hydroxyl, ether, Ethylene-propylene copolymers containing polar groupssuch as amines, amides, imines, imides, hydroxyl, ether. In additionsulfur containing compounds, such as thioglycolic acid and relatedesters have been observed as effective dispersers for gold coated fibersand fillers in binder materials. The invention contemplates that theamount and types of additives will vary for the fiber or filler materialas well as the binder material used, and the above examples areillustrative and should not be construed or interpreted as limiting thescope of the invention.

[0116] Further, a mesh of the conductive fiber and/or filler materialmay be formed in the binder material by providing sufficient amounts ofconductive fiber and/or conductive filler material to form a physicallycontinuous or electrically continuous medium or phase in the bindermaterial. The conductive fibers and/or conductive fillers generallycomprise between about 2 wt. % and about 85 wt. %, such as between about5 wt. % and about 60 wt. %, of the polishing material when combined witha polymeric binder material.

[0117] An interwoven fabric or cloth of the fiber material coated with aconductive material, and optionally, a conductive filler, may bedisposed in the binder. The fiber material coated with a conductivematerial may be interwoven to form a yarn. The yarns may be broughttogether to make a conductive mesh with the help of adhesives orcoatings. The yarn may be disposed as a conductive element in apolishing pad material or may be woven into a cloth or fabric.

[0118] Alternatively, the conductive fibers and/or fillers may becombined with a bonding agent to form a composite conductive polishingmaterial. Examples of suitable bonding agents include epoxies,silicones, urethanes, polyimides, a polyamide, a fluoropolymer,fluorinated derivatives thereof, or combinations thereof. Additionalconductive material, such as conductive polymers, additional conductivefillers, or combinations thereof, may be used with the bonding agent forachieving desired electrical conductivity or other polishing articleproperties. The conductive fibers and/or fillers may include betweenabout 2 wt. % and about 85 wt. %, such as between about 5 wt. % andabout 60 wt. %, of the composite conductive polishing material.

[0119] The conductive fiber and/or filler material may be used to formconductive polishing materials or articles having bulk or surfaceresistivity of about 50 Ω-cm or less, such as a resistivity of about 3Ω-cm or less. In one aspect of the polishing article, the polishingarticle or polishing surface of the polishing article has a resistivityof about 1 Ω-cm or less. Generally, the conductive polishing material orthe composite of the conductive polishing material and conventionalpolishing material are provided to produce a conductive polishingarticle having a bulk resistivity or a bulk surface resistivity of about50 Ω-cm or less. An example of a composite of the conductive polishingmaterial and conventional polishing material includes gold or carboncoated fibers which exhibit resistivities of 1 Ω-cm or less, disposed ina conventional polishing material of polyurethane in sufficient amountsto provide a polishing article having a bulk resistivity of about 10Ω-cm or less.

[0120] The conductive polishing materials formed from the conductivefibers and/or fillers described herein generally have mechanicalproperties that do not degrade under sustained electric fields and areresistant to degradation in acidic or basic electrolytes. The conductivematerial and any binder material used are combined to have equivalentmechanical properties, if applicable, of conventional polishingmaterials used in a conventional polishing article. For example, theconductive polishing material, either alone or in combination with abinder material, has a hardness of about 100 or less on the Shore DHardness scale for polymeric materials as described by the AmericanSociety for Testing and Materials (ASTM), headquartered in Philadelphia,Pennsylvania. In one aspect, the conductive material has a hardness ofabout 80 or less on the Shore D Hardness scale for polymeric. materials.The conductive polishing portion 310 generally includes a surfaceroughness of about 500 microns or less. The properties of the polishingpad are generally designed to reduce or minimize scratching of thesubstrate surfaces during mechanical polishing and when applying a biasto the substrate surface.

[0121] Polishing Article Structures

[0122] In one aspect, the polishing article is composed of a singlelayer of conductive polishing material described herein disposed on asupport. In another aspect, the polishing article may comprise aplurality of material layers including at least one conductive materialon the substrate surface or providing for a conductive surface forcontacting a substrate and at least one article support portion orsub-pad.

[0123]FIG. 3 is a partial cross-sectional view of one embodiment of apolishing article 205. Polishing article 205 illustrated in FIG. 3comprises a composite polishing article having a conductive polishingportion 310 for polishing a substrate surface and an article support, orsub-pad, portion 320.

[0124] The conductive polishing portion 310 may comprise a conductivepolishing material including the conductive fibers and/or conductivefillers as described herein. For example, the conductive polishingportion 310 may include a conductive material comprising conductivefibers and/or conductive fillers dispersed in a polymeric material. Theconductive fillers may be disposed in a polymer binder. The conductivefillers may include soft conductive materials disposed in a polymerbinder. Soft conductive materials generally have a hardness and modulusless than or equal to about that of copper. Examples of soft conductivematerials include gold, tin, palladium, palladium-tin alloys, platinum,and lead, among other conductive metals, alloys and ceramic compositessofter than copper. The invention contemplates the use of otherconductive fillers harder than copper if their size is small enough notto scratch polishing substrate. Further, the conductive polishingportion may include one or more loops, coils, or rings of conductivefibers, or conductive fibers interwoven to form a conductive fabric orcloth. The conductive polishing portion 310 may also be comprised ofmultiple layers of conductive materials, for example, multiple layers ofconductive cloth or fabric.

[0125] One example of the conductive polishing portion 310 includes goldcoated nylon fibers and graphite particles disposed in polyurethane.Another example includes graphite particles and/or carbon fibersdisposed in polyurethane or silicone. Another example includes gold ortin particles dispersed in polyurethane matrix.

[0126] In another embodiment, the conductive polishing portion 310 mayhave abrasive particles 360 disposed therein. At least some of theabrasive particles 360 are exposed on an upper polishing surface 370 ofthe conductive polishing portion 310. The abrasive particles 360generally are configured to remove the passivation layer of the metalsurface of the substrate being polished, thereby exposing the underlyingmetal to the electrolyte and electrochemical activity, thereby enhancingthe rate of polishing during processing. Examples of abrasive particles360 include ceramic, inorganic, organic, or polymer particle strongenough to break the passivation layer formed at the metal surface.Polymer particles may be solid or spongy to tailor the wear rate of thepolishing portion 310.

[0127] The article support portion 320 generally has the same or smallerdiameter or width of the conductive polishing portion 310. However, theinvention contemplates the article support portion 320 having a greaterwidth or diameter than the conductive polishing portion 310. While thefigures herein illustrate a circular conductive polishing portion 310and article support portion 320, the invention contemplates that theconductive polishing portion 310, the article support portion 320, orboth may have different shapes such as rectangular surfaces orelliptical surfaces. The invention further contemplates that theconductive polishing portion 310, the article support portion 320, orboth, may form a linear web or belt of material.

[0128] The article support portion 320 may comprise inert materials inthe polishing process and are resistant to being consumed or damagedduring ECMP. For example, the article support portion may be comprisedof a conventional polishing materials, including polymeric materials,for example, polyurethane and polyurethane mixed with fillers,polycarbonate, polyphenylene sulfide (PPS),ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylenepolymers, or combinations thereof, and other polishing materials used inpolishing substrate surfaces. The article support portion 320 may be aconventional soft material, such as compressed felt fibers impregnatedwith urethane, for absorbing some of the pressure applied between thepolishing article 205 and the carrier head 130 during processing. Thesoft material may have a Shore A hardness between about 20 and about 90.

[0129] Alternatively, the article support portion 320 may be made from aconductive material compatible with surrounding electrolyte that wouldnot detrimentally affect polishing including conductive noble metals ora conductive polymer, to provide electrical conduction across thepolishing article. Examples of noble metals include gold, platinum,palladium, iridium, rhenium, rhodium, rhenium, ruthenium, osmium, andcombinations thereof, of which gold and platinum are preferred.Materials that are reactive with the surrounding electrolyte, such ascopper, may be used if such materials are isolated from the surroundingelectrolyte by an inert material, such as a conventional polishingmaterial or a noble metal.

[0130] When the article support portion 320 is conductive, the articlesupport portion 320 may have a greater conductivity, i.e., lowerresistivity, than the conductive polishing portion 310. For example, theconductive polishing portion 310 may have a resistivity of about 1.0Ω-cm or less as compared to an article support portion 320 comprisingplatinum, which has a resistivity 9.81 μΩ-cm at 0° C. A conductivearticle support portion 320 may provide for uniform bias or current tominimize conductive resistance along the surface of the article, forexample, the radius of the article, during polishing for uniform anodicdissolution across the substrate surface. A conductive article supportportion 320 may be coupled to a power source for transferring power tothe conductive polishing portion 310.

[0131] Generally, the conductive polishing portion 310 is adhered to thearticle support portion 320 by a conventional adhesive suitable for usewith polishing materials and in polishing processes. The inventioncontemplates the use of other means to attach the conductive polishingportion 310 onto the article support portion 320 such as compressionmolding and lamination. The adhesive may be conductive or dielectricdepending on the requirements of the process or the desires of themanufacturer. The article support portion 320 may be affixed to asupport, such as disc 206, by an adhesive or mechanical clamp.Alternatively, if polishing article 205 only includes a conductivepolishing portion 310, the conductive polishing portion may be affixedto a support, such as disc 206, by an adhesive or mechanical clamp

[0132] The conductive polishing portion 310 and the article supportportion 320 of the polishing article 205 are generally permeable to theelectrolyte. A plurality of perforations may be formed, respectively, inthe conductive polishing portion 310 and the article support portion 320to facilitate fluid flow therethrough. The plurality of perforationsallows electrolyte to flow through and contact the surface duringprocessing. The perforations may be inherently formed duringmanufacturing, such as between weaves in a conductive fabric or cloth,or may be formed and patterned through the materials by mechanicalmeans. The perforations may be formed partially or completely througheach layer of the polishing article 205. The perforations of theconductive polishing portion 310 and the perforations of the articlesupport portion 320 may be aligned to facilitate fluid flowtherethrough.

[0133] Examples of perforations 350 formed in the polishing article 205may include apertures in the polishing article having a diameter betweenabout 0.02 inches (0.5 millimeters) and about 0.4 inches (10 mm). Thethickness of the polishing article 205 may be between about 0.1 mm andabout 5 mm. For example, perforations may be spaced between about 0.1inches and about 1 inch from one another.

[0134] The polishing article 205 may have a perforation density betweenabout 20% and about 80% of the polishing article in order to providesufficient mass flow of electrolyte across the polishing articlesurface. However, the invention contemplates perforation densities belowor above the perforation density described herein that may be used tocontrol fluid flow therethrough. In one example, a perforation densityof about 50% has been observed to provide sufficient electrolyte flow tofacilitate uniform anodic dissolution from the substrate surface.Perforation density is broadly described herein as the volume ofpolishing article that the perforations comprise. The perforationdensity includes the aggregate number and diameter or size of theperforations, of the surface or body of the polishing article whenperforations are formed in the polishing article 205.

[0135] The perforation size and density is selected to provide uniformdistribution of electrolyte through the polishing article 205 to asubstrate surface. Generally, the perforation size, perforation density,and organization of the perforations of both the conductive polishingportion 310 and the article support portion 320 are configured andaligned to each other to provide for sufficient mass flow of electrolytethrough the conductive polishing portion 310 and the article supportportion 320 to the substrate surface.

[0136] Grooves may be disposed in the polishing article 205 to promoteelectrolyte flow across the polishing article 205 to provide effectiveor uniform electrolyte flow with the substrate surface for anodicdissolution or electroplating processes. The grooves may be partiallyformed in a single layer or through multiple layers. The inventioncontemplates grooves being formed in the upper layer or polishingsurface that contacts the substrate surface. To provide increased orcontrolled electrolyte flow to the surface of the polishing article, aportion or plurality of the perforations may interconnect with thegrooves. Alternatively, the all or none of the perforations mayinterconnect with the grooves disposed in the polishing article 205.

[0137] Examples of grooves used to facilitate electrolyte flow includelinear grooves, arcuate grooves, annular concentric grooves, radialgrooves, and helical grooves among others. The grooves formed in thearticle 205 may have a cross-section that is square, circular,semi-circular, or any other shape that may facilitate fluid flow acrossthe surface of the polishing article. The grooves may intersect eachother. The grooves may be configured into patterns, such as anintersecting X-Y pattern disposed on the polishing surface or anintersecting triangular pattern formed on the polishing surface, orcombinations thereof, to improve electrolyte flow over the surface ofthe substrate.

[0138] The grooves may be spaced between about 30 mils and about 300mils apart from one another. Generally, grooves formed in the polishingarticle have a width between about 5 mils and about 30 mils, but mayvary in size as required for polishing. An example of a groove patternincludes grooves of about 10 mils wide spaced about 60 mils apart fromone another. Any suitable groove configuration, size, diameter,cross-sectional shape, or spacing may be used to provide the desiredflow of electrolyte. Additional cross sections and groove configurationsare more fully described in co-pending U.S. Patent ProvisionalApplication Serial No. 60/328,434, filed on Oct. 11, 2001, entitled“Method And Apparatus For Polishing Substrates”, which is incorporatedherein by reference in its entirety.

[0139] Electrolyte transport to the surface of the substrate may beenhanced by intersecting some of the perforations with the grooves toallow electrolyte to enter through one set of perforation, be evenlydistributed around the substrate surface by the grooves, used inprocessing a substrate, and then processing electrolyte is refreshed byadditional electrolyte flowing through the perforations. An example of apad perforation and grooving is more fully described in U.S. patentapplication Ser. No. 10/026,854, filed Dec. 20, 2001, which isincorporated by reference in its entirety.

[0140] Examples of polishing articles having perforations and groovesare as follows. FIG. 4 is a top plan view of one embodiment of a groovedpolishing article. A round pad 440 of the polishing article 205 is shownhaving a plurality of perforations 446 of a sufficient size andorganization to allow the flow of electrolyte to the substrate surface.The perforations 446 can be spaced between about 0.1 inches and about 1inch from one another. The perforations may be circular perforationshaving a diameter of between about 0.02 inches (0.5 millimeters) andabout 0.4 inches (10 mm). Further the number and shape of theperforations may vary depending upon the apparatus, processingparameters, and ECMP compositions being used.

[0141] Grooves 442 are formed in the polishing surface 448 of thepolishing article 205 therein to assist transport of fresh electrolytefrom the bulk solution from basin 202 to the gap between the substrateand the polishing article. The grooves 442 may have various patterns,including a groove pattern of substantially circular concentric grooveson the polishing surface 448 as shown in FIG. 4, an X-Y pattern as shownin FIG. 5 and a triangular pattern as shown in FIG. 6.

[0142]FIG. 5 is a top plan view of another embodiment of a polishing padhaving grooves 542 disposed in an X-Y pattern on the polishing portion548 of a polishing pad 540. Perforations 546 may be disposed at theintersections of the vertically and horizontally disposed grooves, andmay also be disposed on a vertical groove, a horizontal groove, ordisposed in the polishing article 548 outside of the grooves 542. Theperforations 546 and grooves 542 are disposed in the inner diameter 544of the polishing article and the outer diameter 550 of the polishing pad540 may be free of perforations and grooves and perforations.

[0143]FIG. 6 is another embodiment of patterned polishing article 640.In this embodiment, grooves may be disposed in an X-Y pattern withdiagonally disposed grooves 645 intersecting the X-Y patterned grooves642. The diagonal grooves 645 may be disposed at an angle from any ofthe X-Y grooves 642, for example, between about 30° and about 60° fromany of the X-Y grooves 642. Perforations 646 may be disposed at theintersections of the X-Y grooves 642, the intersections of the X-Ygrooves 642 and diagonal grooves 645, along any of the grooves 642 and645, or disposed in the polishing article 648 outside of the grooves 642and 645. The perforations 646 and grooves 642 are disposed in the innerdiameter 644 of the polishing article and the outer diameter 650 of thepolishing pad 640 may be free of perforations and grooves.

[0144] Additional examples of groove patterns, such as spiralinggrooves, serpentine grooves, and turbine grooves, are more fullydescribed in co-pending U.S. Patent Provisional Application Serial No.60/328,434, filed on Oct. 11, 2001, entitled “Method And Apparatus ForPolishing Substrates”, which is incorporated herein by reference in itsentirety.

[0145] In addition to the perforations and grooves in the polishingarticle 205, the conductive polishing portion 310 may be embossed toinclude surface texture. The embossment may improve the transportationof electrolytes, removed substrate materials, by products, andparticles. The embossment may also reduce scratches to polishingsubstrate and modify the friction between polishing substrate and thepolishing article 205. The embossed surface textures distributeuniformly across the conductive polishing portion 310. Embossed surfacetextures may include structures such as pyramids, islands, crosses alongwith circular, rectangular and square shapes, among other geometricforms. The invention contemplates other texture structures embossed onconductive polishing portion 310. The embossed surface may cover 5 to 95percent surface area of the conductive polishing portion 310, such asbetween 15 percent and 90 percent surface area of the conductivepolishing portion 310.

[0146] Conductive Polishing Surfaces

[0147]FIG. 7A is a top sectional view of one embodiment of a conductivecloth or fabric 700 that may be used to form a conductive polishingportion 310 of the polishing article 205. The conductive cloth of fabricis composed of interwoven fibers 710 coated with a conductive materialas described herein.

[0148] In one embodiment, a weave or basket-weave pattern of theinterwoven fibers 710 in the vertical 720 and horizontal 730 (shown inthe plane of FIG. 7A) directions is illustrated in FIG. 7A. Theinvention contemplates other form of fabrics, such as yarns, ordifferent interwoven, web, or mesh patterns to form the conductive clothor fabric 700. In one aspect, the fibers 710 are interwoven to providepassages 740 in the fabric 700. The passages 740 allow electrolyte orfluid flow, including ions and electrolyte components, through thefabric 700. The conductive fabric 700 may be disposed in a polymericbinder, such as polyurethane. Conductive fillers may also be disposed insuch a polymeric binder.

[0149]FIG. 7B is a partial cross-sectional view of the conductive clothor fabric 700 disposed on the article support portion 320 of the article205. The conductive cloth or fabric 700 may be disposed as one or morecontinuous layers over the article support portion 320 including anyperforations 350 formed in the article support portion 320. The cloth orfabric 700 may be secured to the article support portion 320 by anadhesive. The fabric 700 is adapted to allow electrolyte flow throughthe fibers, weaves, or passages formed in the cloth or fabric 700 whenimmersed in an electrolyte solution. Optionally an interposed layer maybe included between the cloth or fabric 700 and article support portion320. The interposed layer is permeable or includes perforations alignedwith the perforations 350 for the electrolyte flow through the article205.

[0150] Alternatively, the fabric 700 may also be perforated to increaseelectrolyte flow therethrough if the passages 740 are determined to notbe sufficient to allow effective flow of electrolyte through the fabric700, i.e., metal ions cannot diffuse through. The fabric 700 istypically adapted or perorated to allow flow rates of electrolytesolutions of up to about 20 gallons per minute.

[0151]FIG. 7C is a partial cross-sectional view of the cloth or fabric700 may be patterned with perforations 750 to match the pattern ofperforations 350 in the article support portion 320. Alternatively, someor all of the perforations 750 of the conductive cloth or fabric 700 maynot be aligned with the perforations 350 of the article support portion320. Aligning or non-aligning of perforations allow the operator ormanufacturer to control the volume or flow rate of electrolyte throughthe polishing article to contact the substrate surface.

[0152] An example of the fabric 700 is an interwoven basket weave ofbetween about 8 and about 10 fibers wide with the fiber comprising anylon fiber coated with gold. An example of the fiber is a nylon fiber,about 0.1 μm of cobalt, copper, or nickel material disposed on the nylonfiber, and about 2 μm of gold disposed on the cobalt, copper, or nickelmaterial.

[0153] Alternatively, a conductive mesh may be used in place of theconductive cloth or fabric 700. The conductive mesh may comprisesconductive fibers, conductive fillers, or at least a portion of aconductive cloth 700 disposed in or coated with a conductive binder. Theconductive binder may comprise a non-metallic conductive polymer or acomposite of conductive material disposed in a polymeric compound. Amixture of a conductive filler, such as graphite powder, graphiteflakes, graphite fibers, carbon fibers, carbon powder, carbon black,metallic particles or fibers coated in a conductive material, and apolymeric material, such as polyurethane, may be used to form theconductive binder. The fibers coated with a conductive material asdescribed herein may be used as a conductive filler for use in theconductive binders. For example, carbon fibers or gold-coated nylonfibers may be used to form a conductive binder.

[0154] The conductive binder may also include additives if needed toassist the dispersion of conductive fillers and/or fibers, improveadhesion between polymer and fillers and/or fibers, and improve adhesionbetween the conductive foil and the conductive binder, as well as toimprove of mechanical, thermal and electrical properties of conductivebinder. Examples of additives to improve adhesion include epoxies,silicones, urethanes, polyimides, or combinations thereof for improvedadhesion.

[0155] The composition of the conductive fillers and/or fibers andpolymeric material may be adapted to provide specific properties, suchas conductivity, abrasion properties, durability factors. For exampleconductive binders comprising between about 2 wt. % and about 85 wt. %of conductive fillers may be used with the articles and processesdescribed herein. Examples of materials that may be used as conductivefillers and conductive binders are more fully described in U.S. patentapplication Ser. No. 10/033,732, filed Dec. 27, 2001, which isincorporated herein by reference in its entirety.

[0156] The conductive binder may have a thickness of between about 1microns and 10 millimeters, such as between about 10 microns and about 1millimeter thick. Multiple layers of conductive binders may be appliedto the conductive mesh. The conductive mesh may be used in the samemanner as the conductive cloth or fabric 700 as shown in FIGS. 7B and7C. The conductive binder may be applied in multiple layers over theconductive mesh. In one aspect, the conductive binder is applied to theconductive mesh after the mesh has been perforated to protect theportion of the mesh exposed from the perforation process.

[0157] Additionally, a conductive primer may be disposed on theconductive mesh before application of a conductive binder to improveadhesion of the conductive binder to the conductive mesh. The conductiveprimer may be made of similar material to the conductive binder fiberswith a composition modified to produce properties having a greaterintermaterial adhesion than the conductive binder. Suitable conductiveprimer materials may have resistivities below about 100 Ω-cm, such asbetween 0.001 Ω-cm and about 32 Ω-cm.

[0158] Alternatively, a conductive foil may be used in place of theconductive cloth or fabric 700 as shown in FIG. 7D. The conductive foilgenerally includes a metal foil 780 disposed in or coated with aconductive binder 790 on the support layer 320. Examples of materialforming metal foils include metal coated fabrics, conductive metals suchas copper, nickel, and cobalt, and noble metals, such as gold, platinum,palladium, iridium, rhenium, rhodium, rhenium, ruthenium, osmium, tin,lead, and combinations thereof, of which gold, tin and platinum arepreferred. The conductive foil may also include a nonmetallic conductivefoil sheet, such as a copper sheet, carbon fiber woven sheet foil. Theconductive foil may also include a metal coated cloth of a dielectric orconductive material, such as copper, nickel, tin or gold coating a clothof nylon fibers. The conductive foil may also comprise a fabric ofconductive or dielectric material coated with a conductive bindermaterial as described herein. The conductive foil may also comprise awire frame, screen or mesh of interconnecting conductive metal wires orstrips, such as copper wire, which may be coated with a conductivebinder material as described herein. The invention contemplates the useof other material in forming the metal foil described herein.

[0159] A conductive binder 790 as described herein may encapsulate themetal foil 780, which allows the metal foil 780 to be conductive metalsthat are observed to react with the surrounding electrolyte, such ascopper. The conductive foil may be perforated with a plurality ofperforation 750 as described herein. While not shown, the conductivefoil may be coupled to a conductive wire to power supply to bias thepolishing surface.

[0160] The conductive binder 790 may be as described for the conductivemesh or fabric 700 and may be applied in multiple layers over the metalfoil 780. In one aspect, the conductive binder 790 is applied to themetal foil 780 after the metal foil 780 has been perforated to protectthe portion of the metal foil 780 exposed from the perforation process.

[0161] The conductive binder described herein may be disposed ontoconductive fabric 700, foil 780, or mesh by casting liquid stateadhesive or binder onto the fabric 700, foil 780 or mesh. The binder isthen solidified on the fabric, foil or mesh after drying and curing.Other suitable processing methods including injection mold, compressionmold, lamination, autoclave, extrusion, or combinations thereof may beused to encapsulate the conductive fabric, mesh, or foil. Boththermoplastic and thermosetting binders may be used for thisapplication.

[0162] Adhesion between the conductive binder and the metal foilcomponents of the conductive foil may be enhanced by perforating themetal foil with a plurality of perforations having a diameter or widthbetween about 0.1 μm and about 1 mm or by applying a conductive primerbetween the metal foil and the conductive binder. The conductive primermay be of the same material as the conductive primer for the meshdescribed herein.

[0163]FIG. 7E is a sectional view of another embodiment of a conductivecloth or fabric 798 that may be used to form a lower layer 792 of aconductive polishing portion 310 of the polishing article 205. Theconductive cloth of fabric may be comprised of interwoven oralternatively non-woven fibers 710. The fibers 710 may be formed from orcoated with a conductive material as described above. Examples ofnon-woven fibers include spun-bond or melt blown polymers among othernon-woven fabrics.

[0164] The conductive polishing portion 310 includes an upper layer 794comprised of a conductive material. The upper layer 794 includes apolishing surface 796 disposed opposite the lower layer 792. The upperlayer 794 may have sufficient thickness to smooth out the irregularitiesof the underlying lower layer 792, thereby providing a generally flatand planar polishing surface 796 for contacting the substrate duringprocessing. In one embodiment, the polishing surface 796 has a thicknessvariation of less than or equal to about ±1 mm and a surface roughnessof less than or equal to about 500 micron meter.

[0165] The upper layer 794 may be comprised of any conductive material.In one embodiment, the upper layer 794 is formed from a soft materialsuch as gold, tin, palladium, palladium-tin alloys, platinum, or lead,among other conductive metals, alloys and ceramic composites softer thancopper. The upper layer 794 may optionally include abrasive materialdisposed therein as described above to assist in removing thepassivation layer disposed on the metal surface of the substrate beingpolished.

[0166] Alternatively, the upper layer 794 may be comprised of anon-conductive material that substantially covers the conductivepolishing portion 310 yet leaves at least a portion of the conductivepolishing portion exposed such that the conductive polishing portion 310may be electrically coupled to a substrate being polished on the upperlayer 794. In such a configuration, the upper layer 794 assists inreducing scratching and prevents the conductive portion 310 fromentering any exposed features during polishing. A non-conductive upperlayer 794 may include a plurality of perforations that allow theconductive polishing portion 310 to remain exposed.

[0167]FIG. 7F is another embodiment of a polishing article 205 having awindow 702 formed therein. The window 702 is configured to allow asensor 704 positioned below the polishing article 205 to sense a metricindicative of polishing performance. For example, the sensor 704 may bean eddy current sensor or an interferometer, among other sensors. In oneembodiment, the sensor an interferometer capable of generating acollimated light beam, which during processing, is directed at andimpinges on a side of the substrate 114 that is being polished. Theinterference between reflected signals is indicative of the thickness ofthe layer of material being polished. One sensor that may be utilized toadvantage is described in U.S. Pat. No. 5,893,796, issued Apr. 13, 1999,to Birang, et al., which is hereby incorporated by reference in itsentirety.

[0168] The window 702 includes a fluid barrier 706 that substantiallyprevents processing fluids from reaching the area of the disc 206housing the sensor 704. The fluid barrier 706 is generally selected betransmissive (e.g., to have minimal or no effect or interference) to thesignals passing therethrough. The fluid barrier 706 may be a separateelement, such as a block of polyurethane coupled to the polishingarticle 205 within the window 702, or be one or more of the layerscomprising the polishing article 205, for example, a sheet of mylarunderlying the conductive portion 310 or the article support, orsub-pad, portion 320. Alternatively, fluid barrier 706 may be disposedin the layers disposed between the polishing article 205 and the disc206, such as the electrode 204 or other layer. In yet anotheralternative configuration, the fluid barrier 706 may be disposed in apassage 708 aligned with the window 702 in which the sensor 704 resides.In embodiments wherein the conductive portion 310 comprises multiplylayers, for example, an upper layer 794 and a lower layer 792, thetransparent material 706 may be disposed in at least one layercomprising the conductive portion 310 as shown in FIG. 7F. It iscontemplated that other configurations of conductive polishing articles,including those embodiments described herein along with otherconfigurations, may be adapted to include a window.

[0169] Conductive Elements in Polishing Surfaces

[0170] In another aspect, the conductive fibers and fillers describedherein may be used to form distinct conductive elements disposed in apolishing material to form the conductive polishing article 205 of theinvention. The polishing material may be a conventional polishingmaterial or a conductive polishing material, for example, a conductivecomposite of conductive fillers or fibers disposed in the polymer asdescribed herein. The surface of the conductive elements may form aplane with the surface of the polishing article or may extend above aplane of the surface of the polishing article. Conductive elements mayextend up to about 5 millimeters above the surface of the polishingarticle.

[0171] While the following illustrate the use of conductive elementshaving a specific structure and arrangement in the polishing material,the invention contemplates that individual conductive fibers andfillers, and materials made therefrom, such as fabrics, may also beconsidered conductive elements. Further, while not shown, the followingpolishing article descriptions may include polishing articles havingperforation and grooving patterns described herein and shown in FIGS.4-6, with configurations to the patterns to incorporate the conductiveelements described herein as follows.

[0172] FIGS. 8A-8B depict a top and a cross-sectional schematic view ofone embodiment of a polishing article 800 having conductive elementsdisposed therein. The polishing article 800 generally comprises a body810 having a polishing surface 820 adapted to contact the substratewhile processing. The body 810 typically comprises a dielectric orpolymeric material, such as a dielectric polymer material, for example,polyurethane.

[0173] The polishing surface 820 has one or more openings, grooves,trenches, or depressions 830 formed therein to at least partiallyreceive conductive elements 840. The conductive elements 840 may begenerally disposed to have a contact surface 850 co-planar or extendingabove a plane defined by the polishing surface 820. The contact surface850 is typically configured, such as by having a compliant, elastic,flexible, or pressure moldable surface, to maximize electrical contactof the conductive elements 840 when contacting the substrate. Duringpolishing, a contact pressure may be used to urge the contact surface850 into a position co-planar with the polishing surface 820.

[0174] The body 810 is generally made permeable to the electrolyte by aplurality of perforations 860 formed therein as described herein. Thepolishing article 800 may have a perforation density between about 20%and about 80% of the surface area of the polishing article 810 toprovide sufficient electrolyte flow to facilitate uniform anodicdissolution from the substrate surface.

[0175] The body 810 generally comprises a dielectric material such asthe conventional polishing materials described herein. The depressions830 formed in the body 810 are generally configured to retain theconductive elements 840 during processing, and accordingly may vary inshape and orientation. In the embodiment depicted in FIG. 8A, thedepressions 830 are grooves having a rectangular cross section disposedacross the polishing article surface and forming an interconnecting “X”or cross pattern 870 at the center of the polishing article 800. Theinvention contemplates additional cross sections, such as inversetrapezoidal and rounded curvature where the groove contacts thesubstrate surface as described herein.

[0176] Alternatively, the depressions 830 (and conductive elements 840disposed therein) may be disposed at irregular intervals, be orientatedradially, parallel, or perpendicular, and may additionally be linear,curved, concentric, involute curves, or other cross-sectional areas.

[0177]FIG. 8C is a top schematic view of a series of individualconductive elements 840 radially disposed in the body 810, each element840 separated physically or electrically by a spacer 875. The spacer 875may be a portion of dielectric polishing material or a dielectricinterconnect for the elements, such as a plastic interconnect.Alternatively, the spacer 875 may be a section of the polishing articledevoid of either the polishing material or conductive elements 840 toprovide an absence of physical connection between the conductiveelements 840. In such a separate element configuration, each conductiveelement 840 may be individually connected to a power source by aconductive path 890, such as a wire.

[0178] Referring back to FIGS. 8A and 8B, the conductive elements 840disposed in the body 810 are generally provided to produce a bulkresistivity or a bulk surface resistivity of about 20 Ω-cm or less. Inone aspect of the polishing article, the polishing article has aresistivity of about 2 Ω-cm or less. The conductive elements 840generally have mechanical properties that do not degrade under sustainedelectric fields and are resistant to degradation in acidic or basicelectrolytes. The conductive elements 840 are retained in thedepressions 830 by press fit, clamping, adhesive, or by other methods.

[0179] In one embodiment, the conductive elements 840 are sufficientlycompliant, elastic, or flexible to maintain electrical contact betweenthe contact surface 850 and the substrate during processing. Sufficientcompliant, elastic, or flexible materials for the conductive element 840may have an analogous hardness of about 100 or less on the Shore DHardness scale compared to the polishing material. A conductive element840 having an analogous hardness of about 80 or less on the Shore DHardness scale for polymeric materials may be used. A compliantmaterial, such as flexible or bendable fibers of material, may also beused as the conductive elements 840. The conductive element 840 may bemore compliant than polishing material to avoid high local pressureintroduced by conductive element 840 during polishing.

[0180] In the embodiment depicted in FIGS. 8A and 8B, the conductiveelements 840 are embedded in the polishing surface 810 disposed on anarticle support or sub-pad 815. Perforations 860 are formed through bothpolishing surface 810 and the article support 815 around conductiveelements 840.

[0181] An example of the conductive elements 840 includes dielectric orconductive fibers coated with a conductive material or conductivefillers blended with a polymeric material, such as a polymer basedadhesive, to make a conductive (and wear resistant) composite asdescribed herein. The conductive elements 840 may also compriseconductive polymeric material or other conductive materials as describedherein to improve electrical properties. For example, the conductiveelements comprise a composite of a conductive epoxy and a conductivefiber comprising a nylon fiber coated with gold, such as a nylon fibercoated with about 0.1 μm of cobalt, copper, or nickel disposed on thenylon fiber, and about 2 μm of gold disposed on the a nylon fiber, andcarbon or graphite fillers to improve the composite's conductivity,which is deposited in a body of polyurethane.

[0182]FIG. 8D is a cross-sectional schematic view of another embodimentof a polishing article 800 having conductive elements disposed therein.The conductive elements 840 may be generally disposed to have a contactsurface coplanar or extending above a plane defined by the polishingsurface 820. The conductive elements 840 may include the conductivefabric 700, as described herein, disposed, encapsulated or wrappedaround a conductive member 845. Alternatively individual conductivefibers and/or fillers may be disposed, encapsulated, or wrapped aroundthe conductive member 845. The conductive member 845 may comprise ametal, such as a noble metal described herein, or other conductivematerials, such as copper, suitable for use in electropolishingprocesses. The conductive element 840 may also comprise a composite ofthe fabric and a binder material as described herein with the fabricforming an outer contact portion of the conductive element 840 and thebinder typically forming an inner support structure. The conductiveelement 840 may also comprise a hollow tube having a rectangularcross-sectional area with the walls of the tube formed of rigidconductive fabric 700 and a bonding agent as described herein.

[0183] A connector 890 is utilized to couple the conductive elements 840to a power source (not shown) to electrically bias the conductiveelements 840 during processing. The connector 890 is generally a wire,tape or other conductor compatible with process fluids or having acovering or coating that protects the connector 890 from the processfluids. The connector 890 may be coupled to the conductive elements 840by molding, soldering, stacking, brazing, clamping, crimping, riveting,fastening, conductive adhesive or by other methods or devices. Examplesof materials that may be utilized in the connector 890 include insulatedcopper, graphite, titanium, platinum, gold, aluminum, stainless steel,and HASTELOY® conductive materials among other materials.

[0184] Coatings disposed around the connectors 890 may include polymerssuch as fluorocarbons, poly-vinyl chloride (PVC) and polyimide. In theembodiment depicted in FIG. 8A, one connector 890 is coupled to eachconductive element 840 at the perimeter of the polishing article 800.Alternatively, the connectors 890 may be disposed through the body 810of the polishing article 800. In yet another embodiment, the connector890 may be coupled to a conductive grid (not shown) disposed in thepockets and/or through the body 810 that electrically couples theconductive elements 840.

[0185]FIG. 9A depicts another embodiment of a polishing material 900.The polishing material 900 includes a body 902 having one or more atleast partially conductive elements 904 disposed on a polishing surface906. The conductive elements 904 generally comprise a plurality offibers, strands, and/or flexible fingers that are compliant or elasticand adapted to contact a substrate surface while processing. The fibersare comprised of an at least partially conductive material, such as afiber composed of a dielectric material coated with a conductivematerial as described herein. The fibers may also be solid or hollow innature to decrease or increase the amount of compliance or flexibilityof the fibers.

[0186] In the embodiment depicted in FIG. 9A, the conductive elements904 are a plurality of conductive sub-elements 913 coupled to a base909. The conductive sub-elements 913 include the at least partiallyelectrically conductive fibers described herein. An example of thesub-elements 913 include a nylon fiber coated with gold as describedherein or carbon fiber. The base 909 also comprises an electricallyconductive material and is coupled to a connector 990. The base 909 mayalso be coated by a layer of conductive material, such as copper, thatdissolves from the polishing pad article during polishing, which isbelieved to extend the processing duration of the conductive fibers.

[0187] The conductive elements 904 generally are disposed in adepression 908 formed in the polishing surface 906. The conductiveelements 904 may be orientated between 0 and 90 degrees relative to thepolishing surface 906. In embodiments where the conductive elements 904are orientated perpendicular to the polishing surface 906, theconductive elements 904 may partially be disposed on the polishingsurface 906.

[0188] The depressions 908 have a lower mounting portion 910 and anupper, clearance portion 912. The mounting portion 910 is configured toreceive the base 909 of the conductive elements 904, and retain theconductive elements 904 by press fit, clamping, adhesive, or by othermethods. The clearance portion 912 is disposed where the depression 908intersects the polishing surface 906. The clearance portion 912 isgenerally larger in cross section than the mounting portion 910 to allowthe conductive elements 904 to flex when contacting a substrate whilepolishing without being disposed between the substrate and the polishingsurface 906.

[0189]FIG. 9B depicts another embodiment of a polishing article 900having a conducting surface 940 and a plurality of discrete conductiveelements 920 formed thereon. The conductive elements 920 comprise fibersof dielectric material coated by a conductive material are verticallydisplaced from the conducting surface 940 of the polishing article 205and are horizontally displaced from each other. The conducting elements920 of the polishing article 900 are generally orientated between 0 to90 degrees relative to a conducting surface 940 and can be inclined inany polar orientation relative to a line normal to the conductingsurface 940. The conductive elements 920 may be formed across the lengthof the polishing pads, as shown in FIG. 9B or only may be disposed inselected areas of the polishing pad. The contact height of theconductive elements 920 above the polishing surface may be up to about 5millimeters. The diameter of the material comprising the conductiveelement 920 is between about 1 mil (thousandths of an inch) and about 10mils. The height above the polishing surface and a diameter of theconductive elements 920 may vary upon the polishing process beingperformed.

[0190] The conductive elements 920 are sufficiently compliant or elasticto deform under a contact pressure while maintaining an electricalcontact with a substrate surface with reduced or minimal scratching ofthe substrate surface. In the embodiment shown in FIG. 9A and 9B, thesubstrate surface may only contact the conductive elements 920 of thepolishing article 205. The conductive elements 920 are positioned so asto provide an uniform current density over the surface of the polishingarticle 205.

[0191] The conductive elements 920 are adhered to the conducting surfaceby a non-conductive, or dielectric, adhesive or binder. Thenon-conductive adhesive may provide a dielectric coating to theconducting surface 940 to provide an electrochemical barrier between theconducting surface 940 and any surrounding electrolyte. The conductingsurface 940 may be in the form of a round polishing pad or a linear webor belt of polishing article 205. A series of perforations (not shown)may be disposed in the conducting surface 940 for provided flow ofelectrolyte therethrough.

[0192] While not shown, the conductive plate may be disposed on asupport pad of conventional polishing material for positioning andhandling of the polishing article 900 on a rotating or linear polishingplaten.

[0193]FIG. 10A depicts a schematic perspective view of one embodiment ofa polishing article 1000 comprised of conductive element 1004. Eachconductive element 1004 generally comprises a loop or ring 1006 having afirst end 1008 and a second end 1010 disposed in a depression 1012formed in the polishing surface 1024. Each conductive element 1004 maybe coupled to an adjoining conductive element to form a plurality ofloops 1006 extending above the polishing surface 1024.

[0194] In the embodiment depicted in FIG. 10A, each loop 1006 isfabricated from a fiber coated by a conductive material and is coupledby a tie wire base 1014 adhered to the depression 1012. An example ofthe loop 1006 is a nylon fiber coated with gold.

[0195] The contact height of the loop 1006 above the polishing surfacemay be between about 0.5 millimeter and about 2 millimeters and thediameter of the material comprising the loop may be between about 1 mil(thousandths of an inch) and about 50 mils. The tie wire base 1014 maybe a conductive material, such as titanium, copper, platinum, orplatinum coated copper. The tie wire base 1014 may also be coated by alayer of conductive material, such as copper, that dissolves from thepolishing pad article during polishing. The use of a layer of conductivematerial on the tie wire base 1014 is believed to be a sacrificial layerthat dissolves in preference of the underlying loop 1006 material or tiewire base 1014 material to extend the life of the conductive element1004. The conductive elements 1004 may be orientated between 0 to 90degrees relative to a polishing surface 1024 and can be inclined in anypolar orientation relative to a line normal to the polishing surface1024. The conductive elements 1004 are coupled to a power source byelectrical connectors 1030.

[0196]FIG. 10B depicts a schematic perspective view of anotherembodiment of a polishing article 1000 comprised of conductive element1004. The conductive element 1004 comprises a singular coil 1005 of awire composed of a fiber coated with a conductive material as describedherein. The coil 1005 is coupled to a conductive member 1007 disposed ona base 1014. The coil 1005 may encircle the conductive member 1007,encircle the base 1014, or be adhered to the surface of the base 1014.The conductive bar may comprise a conductive material, such as gold, andgenerally comprises a conductive material that is chemically inert, suchas gold or platinum, with any electrolyte used in a polishing process.Alternatively, a layer 1009 of sacrificial material, such as copper, isdisposed on the base 1014. The layer 1009 of sacrificial material isgenerally a more chemically reactive material, such as copper, than theconductive member 1007 for preferential removal of the chemicallyreactive material compared to the material of the conductive member 1007and the coil 1005, during an electropolishing aspect, or anodicdissolution aspect, of the polishing process. The conductive member 1007may be coupled to a power source by electrical connectors 1030.

[0197] A biasing member may be disposed between the conductive elementsand the body to provide a bias that urges the conductive elements awayfrom the body and into contact with a substrate surface duringpolishing. An example of a biasing member 1018 is shown in FIG. 10B.However, the invention contemplates that the conductive elements shownherein, for example in FIGS. 8A-8D, 9A, 10A-10D, may use a biasingmember. The biasing member may be a resilient material or deviceincluding a compression spring, a flat spring, a coil spring, a foamedpolymer such as foamed polyurethane (e.g., PORON® polymer), anelastomer, a bladder or other member or device capable of biasing theconductive element. The biasing member may also be a compliant orelastic material, such as compliant foam or aired soft tube, capable ofbiasing the conductive element against and improve contact with thesubstrate surface being polished. The conductive elements biased mayform a plane with the surface of the polishing article or may extendabove a plane of the surface of the polishing article.

[0198]FIG. 10C shows a schematic perspective view of another embodimentof a polishing article 1000 having a plurality of conductive elements1004, disposed in a radial pattern from the center of the substrate tothe edge. The plurality of conductive elements may be displaced fromeach other at intervals of 15°, 30°, 45°, 60°, and 90° degrees, or anyother combinations desired. The conductive elements 1004 are generallyspaced to provide as uniform application of current or power forpolishing of the substrate. The conductive elements may be furtherspaced so as to not contact each other. Wedge portions 1004 of adielectric polishing material of the body 1026 may be configured toelectrically isolate the conductive elements 1004. A spacer or recessedarea 1060 is also formed in the polishing article to also isolate theconductive elements 1004 from each other. The conductive elements 1004may be in the form of loops as shown in FIG. 10A or vertical extendingfibers as shone in FIG. 9B.

[0199]FIG. 10D depicts a schematic perspective view of an alternativeembodiment of the conductive element 1004 of FIG. 10A. The conductiveelement 1004 comprises a mesh or fabric of interwoven conductive fibers1006 as described herein having a first end 1008 and a second end 1010disposed in a depression 1012 formed in. the polishing surface 1024 toform one continuous conductive surface for contact with the substrate.The mesh or fabric may be of one or more layers of interwoven fibers.The mesh or fabric comprising the conductive element 1004 is illustratedas a single layer in FIG. 10D. The conductive element 1004 may becoupled to a conductive base 1014 and may extend above the polishingsurface 1024 as shown in FIG. 10A. The conductive element 1004 may becoupled to a power source by electrical connectors 1030 connected to theconductive base 1014.

[0200]FIG. 10E shows a partial schematic perspective view of anotherembodiment of forming the conductive elements 1004 having loops 1006formed therein and securing the conductive elements to the body 1026 ofthe polishing article. Passages 1050 are formed in the body 1024 of thepolishing article intersecting grooves 1070 for the conductive elements1004. An insert 1055 is disposed in the passages 1050. The insert 1055comprises a conductive material, such as gold or the same material asthe conductive element 1006. Connectors 1030 may then be disposed in thepassages 1050 and contacted with the insert 1055. The connectors 1030are coupled to a power source. Ends 1075 of the conductive element 1004may be contacted with the insert 1055 for flow of power therethrough.The ends 1075 of the conductive element 1004 and the connectors 1030 arethen secured to the conductive insert 1055 by dielectric inserts 1060.The invention contemplated using the passages for every loop 1006 of theconductive element 1004, at intervals along the length of the conductiveelement 1004, or only at the extreme ends of the conductive element1004.

[0201] FIGS. 11A-C are a series of schematic side views illustrating theelastic ability of the loops or rings of conductive materials describedherein. A polishing article 1100 comprises a polishing surface 1110disposed on a sub-pad 1120 formed over a pad support 1130 with groovesor depressions 1140 therein. A conductive element 1142 comprising a loopor ring 1150 of a dielectric material coated by a conductive material isdisposed on a tie base 1155 in the depression 1170 and coupled with anelectrical contact 1145. A substrate 1160 is contacted with thepolishing article 1100 and moved in relative motion with the surface ofthe polishing article 1100. As the substrate contacts the conductiveelement 1142, the loop 1150 compresses into the depression 1140 whilemaintaining electrical contact with the substrate 1160 as shown in FIG.11B. When the substrate is moved a sufficient distance to no longercontact the conductive element 1142, the elastic loop 1150 returns tothe uncompressed shape for additional processing as shown in FIG. 11C.

[0202] Further examples of conductive polishing pads are described inU.S. Provisional Patent Application Serial No. 10/033,732, filed Dec.27, 2001, which is incorporated by reference in its entirety.

[0203] Power Application

[0204] Power may be coupled into the polishing articles 205 describedabove by using a connector as described herein or a power transferencedevice. A power transference device is more fully detailed in U.S.Provisional Patent Application Serial No. 10/033,732, filed Dec. 27,2001, which is incorporated by reference in its entirety.

[0205] Referring back to FIGS. 11A-11C, power may be coupled toconductive elements 1140 by the use of electrical contacts 1145comprising conductive plates or mounts disposed in the grooves ordepressions 1170 formed in the polishing pad. In the embodiment shown inFIG. 11A, the conductive elements 1140 are mounted on plates of a metal,such as gold, which are mounted on a support, such as disc 206, with thepolishing article 1100 as shown in FIG. 2. Alternatively, the electricalcontacts may be disposed on a polishing pad material between aconductive elements and a polishing pad material, for example, betweenthe conductive element 840 and the body 810 as shown in FIGS. 8A and 8B.the electrical contacts are then coupled to a power source by leads (notshown) as described above in FIGS. 8A-8D.

[0206] FIGS. 12A-12D are top and side schematic view of embodiments of apolishing article having extensions connected to a power source (notshown). The power source provides the current carrying capability, i.e.,the anodic bias to a substrate surface for anodic dissolution in an ECMPprocess. The power source may be connected to the polishing article byone or more conductive contacts disposed around the conductive polishingportion and/or the article support portion of the polishing article. Oneor more power sources may be connected to the polishing article by theone or more contacts to allow for generating variable bias or currentacross a, portion of the substrate surface. Alternatively, one or moreleads may be formed in the conductive polishing portion and/or thearticle support portion, which are coupled to a power source.

[0207]FIG. 12A is a top plan view of one embodiment of a conductivepolishing pad coupled to a power source by a conductive connector. Theconductive polishing portion may have extensions, for example, ashoulder or individual plugs, formed in the conductive polishing portion1210 with a greater width or diameter than the article support portion1220. The extensions are coupled to a power source by a connector 1225to provide electrical current to the polishing article 205. In FIG. 12B,extensions 1215 may be formed to extend parallel or laterally from theplane of the conductive polishing portion 1210 and extending beyond thediameter of the polishing support portion 1220. The pattern of theperforation and grooving are as shown in FIG. 6.

[0208]FIG. 12B is a cross-section schematic view of one embodiment of aconnector 1225 coupled to a power source (not shown) via a conductivepathway 1232, such as a wire. The connector comprises an electricalcoupling 1234 connected to the conductive pathway 1232 and electricallycoupled to the conductive polishing portion 1210 of the extension 1215by a conductive fastener 1230, such as a screw. A bolt 1238 may becoupled to the conductive fastener 1230 securing the conductivepolishing portion 1210 therebetween. Spacers 1236, such as washer, maybe disposed between the conductive polishing portion 1210 and thefastener 1230 and bolt 1238. The spacers 1236 may comprise a conductivematerial. The fastener 1230, the electrical coupling 1234, the spacers1236, and the bolt 1238 may be made of a conductive material, forexample, gold, platinum, titanium, aluminum, or copper. If a materialthat may react with the electrolyte is used, such as copper, thematerial may be covered in a material that is inert to reactions withthe electrolyte, such as platinum. While not shown, alternativeembodiments of the conductive fastener may include a conductive clamp,conductive adhesive tape, or a conductive adhesive.

[0209]FIG. 12C is a cross-section schematic view of one embodiment of aconnector 1225 coupled to a power source (not shown) via a support 1260,such as the upper surface of a platen or disc 206 as shown in FIG. 2.The connector 1225 comprises a fastener 1240, such as a screw or bolthaving sufficient length to penetrate through the conductive polishingportion 1210 of the extension 1215 to couple with the support 1260. Aspacer 1242 may be disposed between the conductive polishing portion1210 and the fastener 1240.

[0210] The support is generally adapted to receive the fastener 1240. Anaperture 1246 may be formed in the surface of the support 1260 toreceive the fastener as shown in FIG. 12C. Alternatively, an electricalcoupling may be disposed between the fastener 1240 and the conductivepolishing portion 1210 with the fastener coupled with a support 1260.The support 1260 may be connected to a power source by a conductivepathway 1232, such as a wire, to a power source external to a polishingplaten or chamber or a power source integrated into a polishing platenor chamber to provide electrical connection with the conductivepolishing portion 1210. The conductive path 1232 may be integral withthe support 1260 or extend from the support 1260 as shown in FIG. 12B

[0211] In a further embodiment, the fastener 1240 may be an integratedextension of the support 1260 extending through the conductive polishingportion 1215 and secured by a bolt 1248 as shown in FIG. 12D.

[0212]FIGS. 12E and 12F show side schematic and exploded perspectiveviews of another embodiment of providing power to a polishing article1270 having a power coupling 1285 disposed between a polishing portion1280 and a article support portion 1290. The polishing portion 1280 maybe made of a conductive polishing material as described herein orinclude a plurality of conductive elements 1275 as described herein. Theconductive elements 1275 may be physically isolated from one another asshown in FIG. 12F. The conductive elements 1275 formed in the polishingsurface are adapted to electrically contact the power coupling 1285,such as by a conductive base of the element.

[0213] The power coupling 1285 may comprise a wire interconnectingelements 1275, multiple parallel wires interconnecting elements 1275,multiple wires independently connecting elements 1275, or a wire meshinterconnecting elements connecting elements 1275 to one or more powersources. Independent power sources coupled to independent wires andelements may have varied power applied while interconnected wires andelements may provide uniform power to the elements. The power couplingmay cover a portion or all of the diameter or width of the polishingarticle. The power coupling 1285 in FIG. 12F is an example of a wiremesh interconnecting elements connecting elements 1275. The powercoupling 1285 may be connected to a power source by a conductive pathway1287, such as a wire, to a power source external to a polishing platenor chamber or a power source integrated into a polishing platen orchamber.

[0214] Abrasive Elements in Polishing Surfaces

[0215] FIGS. 13A-B are top and sectional views of another embodiment ofa conductive article 1400. The conductive article 1400 includes abrasivefeatures extending from a polishing surface 1402 of a conductive portion1404 of the conductive article 1400. The abrasive features may beabrasive particles as described with reference to FIG. 3 above, or maybe discreet abrasive elements 1406 as shown in FIGS. 13A-B.

[0216] In one embodiment, the abrasive elements 1406 are bars receivedin respective slots 1408 formed in the polishing surface 1402 of theconductive article 1400. The abrasive elements 1406 generally extendfrom the polishing surface 1402 and are configured to remove thepassivation layer of the metal surface of the substrate being polished,thereby exposing the underlying metal to the electrolyte andelectrochemical activity, thereby enhancing the rate of polishing duringprocessing. The abrasive elements 1406 may be formed from ceramic,inorganic, organic, or polymer material strong enough to break thepassivation layer formed at the metal surface. An example is a bar orstrip made from conventional polishing pad such as polyurethane paddisposed in the conductive article 1400. In the embodiment depicted inFIGS. 13A-B, the abrasive elements 1406 may have hardness of at leastabout 30 Shore D, or hard enough to abrade the passivation layer of thematerial being polished. In one embodiment, the abrasive elements 1406are harder than copper. Polymer particles may be solid or spongy totailor the wear rate of the abrasive elements 1406 relative to thesurrounding conductive portion 1404.

[0217] The abrasive elements 1406 may be configured in various geometricor random configurations on the polishing surface 1402. In oneembodiment, the abrasive elements 1406 are radially oriented on thepolishing surface 1402, however, other orientations such as spiral,grid, parallel and concentric orientations of the abrasive elements 1406are contemplated among other orientations.

[0218] In one embodiment, a resilient member 1410 may be disposed in therespective slots 1408 between the abrasive elements 1406 and theconductive portion 1404. The resilient member 1410 allows the abrasiveelements 1406 to move relative to the conductive portion 1404, therebyproviding enhanced compliance to the substrate for more uniform removalof the passivation layer during polishing. Moreover, the compliance ofthe resilient member 1410 may be selected to tailored the relativepressure applied to the substrate by the abrasive elements 1406 and thepolishing surface 1402 of the conductive portion 1404, thereby balancingremoval rate of the passivation layer against the rate of passivationlayer formation so that the metal layer being polished is minimallyexposed to the abrasive elements 1406 to minimize potential scratchgeneration.

[0219] Conductive Balls Extending from Polishing Surfaces

[0220] FIGS. 14A-D are top and sectional views of alternativeembodiments of a conductive article 1500. The conductive article 1500includes conductive rollers 1506 extending from a polishing surface 1502of an upper portion 1504 of the conductive article 1500. The rollers1506 can be urged down to the same plane of the polishing surface 1502by substrate during polishing. The conductive rollers embedded in theconductive article 1500 are coupled to an external power source 1536 athigh voltage for high removal rate of bulk polishing substrate duringprocessing.

[0221] The conductive rollers 1506 may be fixed relative to the upperportion 1504, or may be free to roll. The conductive rollers 1506 mayballs, cylinders, pins, ellipsoidal or other shapes configured not toscratch the substrate during processing.

[0222] In the embodiment depicted in FIG. 14B, the conductive rollers1506 are plurality of balls disposed in one or more conductive carriers1520. Each conductive carrier 1520 is disposed in a slot 1508 formed inthe polishing surface 1502 of the conductive article 1500. Theconductive rollers 1506 generally extend from the polishing surface 1502and are configured to provide electrical contact with the metal surfaceof the substrate being polished. The conductive rollers 1506 may beformed from any conductive material, or formed from a core 1522 at leastpartially coated with a conductive covering 1524. In the embodimentdepicted in FIG. 14B, the conductive rollers 1506 have a polymer core1522 at least partially covered by a soft conductive material 1524. Anexample is a TORLON™ polymer core coated with conductive gold layerusing copper as seeding layer between TORLON™ and gold layer. Anotherexample is TORLON™ or other polymer core coated with a layer of copperor other conductive material. Other soft conductive materials 1524include, but are not limited to, silver, copper, tin and the like.

[0223] In one embodiment, the polymer core 1522 may be selected from anelastic or a resilient material such as polyurethane that deformed whenthe roller 1506 is in contact with a substrate during polishing. Someexamples of materials that may be utilized for the core 1522 includeelastic organic polymers, ethylene-propylene-diene (EDPM), poly-alkenes,polyalkynes, polyesters, poly-aromatic alkenes/alkynes, polyimide,polycarbonate, polyurethane, and there combinations. Other examples ofcore materials include inorganic polymers, such as siloxane, or organicand inorganic combined materials, such as polysilicon and polysilane. Asthe roller 1506 deforms, the contact area between the roller 1506 andsubstrate increases, thus improving the current flow between the roller1506 and conductive layer disposed on the substrate and therebyimproving polishing results.

[0224] Alternatively, the polymer core 1522 may be made conductive as tomake the covering of the core 1522 with soft conductive material 1524optional. For example, the polymer core 1522 may be doped by otherconductive elements, such as metals, conductive carbon or graphite,among other conductive materials.

[0225] The conductive rollers 1506 may be arranged in various geometricor random configurations on the polishing surface 1502. In oneembodiment, the conductive rollers 1506 are radially oriented on thepolishing surface 1502, however, other orientations such as spiral,grid, parallel and concentric orientations of the conductive rollers1506 are contemplated among other orientations.

[0226] In the embodiment depicted in FIG. 14B, a resilient member 1510may be disposed in the respective slots 1508 between the conductivecarriers 1520 and the conductive portion 1504. The resilient member 1510allows the conductive rollers 1506 (and carrier 1520) to move relativeto the conductive portion 1504, thereby providing enhanced compliance tothe substrate for more uniform electrical contact during polishing.

[0227] In the embodiment depicted in FIG. 14C, the conductive rollers1506 are respectively disposed in a plurality of electrically insulativehousings 1530 that are coupled to the disc 206. Each housing 1530 may becoupled to the disc 206 by welding, adhesives, staking or other methods.In the embodiment depicted in FIG. 14C, the housings 1530 are threadedinto the disc 206.

[0228] The housing 1530 is generally a hollow cylinder that allows theroller 1506 to move vertically, perpendicular to the plane of the disc206 and polishing surface 1502. An upper end of the housing 1530includes a tapered seat 1532 that prevents the roller 1506 from exitingthrough the upper end of the housing 1530. The seat 1532 is configuredto allow at least a portion of the perimeter of the roller 1506 toextend out of the housing 1530 and contact the substrate 114 duringprocessing.

[0229] A contact means 1534 is configured to maintain electrical contactbetween the roller 1506 and the power source 1536. The contact means1534 may be any type of conductive resilient member such as a springform, compression spring, conductive bearing and the like, or otherdevice that allows electrical connection to be maintains betweendifferent positions of the roller 1506 within the housing 1530. Thecontact means 1534 is disposed in the lower end of each of the housings1530. In one embodiment, the contact means 1534 is a flat spring. Thecontact means 1534 may be utilized to bias the roller 1506 away from thedisc 206 and against the seat 1532.

[0230] Alternatively, electrolyte provided from an electrolyte source1544 flowing through the housing 1530 and exiting the housing 1530between the seat 1532 and roller 1506. The flow of electrolyte exitingthe housing 1530 biases the roller 1506 away from the disc 206.

[0231] In yet another embodiment, the roller 1506 may be configured witha specific gravity less than the electrolyte so that the buoyancy of theroller 1506 when the housing 1530 is at least partially filled withelectrolyte biases the roller 1506 away from the disc 206. The roller1506 may be optionally hollow to increase the buoyancy and decrease theinertia of the roller 1506. One housing having a roller coupled to apower source through a contact member that may be adapted to benefitfrom the invention is described in previously incorporated U.S. patentapplication Ser. No. 10/211,626.

[0232] A pad assembly 1540 is disposed on the disc 206. The pad assembly1540 includes a plurality of first apertures 1542 that are configured toallow the housings 1530 to extend at least partially therethrough.Generally, the housing 1530 has a height configured to allow a portionof the perimeter of the roller 1506 to extend above the pad assembly1540 so that the roller 1506 may be displaced to a positionsubstantially flush with the polishing surface 1502 of the pad assembly1540 by the substrate 114 during processing.

[0233] In the embodiment depicted in FIG. 14C, the pad assembly 1540includes a dielectric layer 1550, a subpad 1552 and an electrode 1554.The dielectric layer 1550, the subpad 1552 and the electrode 1554 may becoupled together as a replaceable unit, for example by compressionmolding, staking, fastening, adhering, bonding or by other couplingmethods.

[0234] The dielectric layer 1550 may be similar to the conductiveportion 310 described above. The subpad 1552 may be similar to thearticle support portion 320 described above. The electrode 1554 may besimilar to the electrode 204 described above.

[0235] A second set of apertures 1545 (one of which is shown in FIG.14C) may be formed at least through the dielectric layer 1550 through atleast the dielectric layer 1550 and the subpad 1552 to allow electrolytedisposed on the pad assembly 1540 to provide a current path between theelectrode 1554 and the substrate 114. Optionally, the apertures 1545 mayextend into or through the electrode 1554. The apertures 1545 maypermeable and/or porous portion of the dielectric layer 1550 and thesubpad 1552. A window (not shown) may also be formed in the pad assembly1540 as described above with reference to FIG. 7F to facilitate processcontrol.

[0236] In the embodiment depicted in FIG. 14D, a pad assembly 1560includes at least a conductive layer 1562, a subpad 1564 and anelectrode 1554. The conductive layer 1562, the subpad 1564 and theelectrode 1554 may be coupled together as a replaceable unit. The padassembly 1560 may include first apertures 1570 configured to accept thehousing 1530 and second apertures 1572 to allow electrolyte disposed onthe pad assembly 1560 to establish a current path between the substrate114 and the electrode 1554. The second apertures 1572 may alternativelybe a porous and/or permeable portion of the pad assembly 1560. A window(not shown) may also be formed in the pad assembly 1560 as describedabove

[0237] In one embodiment, the conductive layer 1562 and subpad 1564 maybe configured similar to the conductive layer 310 and article supportportion 320 of the polishing article 205 described above. Alternatively,the pad assembly 1560 may include a conductive backing 1566 and aninterposed pad 1568 disposed between the conductive layer 1562 andsubpad 1564. The conductive backing 1566 and the interposed pad 1568 maybe similarly configured to the conductive backing and the interposed paddescribed under the heading “CONDUCTIVE ARTICLE WITH INTERPOSED PAD”that follows below.

[0238] The conductive backing 1566 is generally coupled to the powersource 1536 through a switch 1574. The conductive backing 1566distributes the potential uniformly across the backside of theconductive layer 1562 so that uniform current is delivered across thediameter of the substrate 114 between the conductive layer 1562 andsubstrate 114 during processing.

[0239] During processing, the switch 1574 is disposed in a first statethat electrically couples the roller 1506 to the power source 1536 whileopening the circuit between the conductive backing 1566 and the powersource 1536. The rollers 1506 allow relatively high current flow betweenthe substrate 114 and electrode 1554 thereby facilitating bulk removalof a conductive layer from the substrate. Once the conductive layer issubstantially removed, the switch 1574 is disposed in a second statethat electrically couples conductive backing 1566 the to the powersource 1536 while opening the circuit between the roller 1506 and thepower source 1536. The conductive backing 1566 provides substantiallyuniform voltage potential across the width of the conductive layer 1562to facilitate removal of residual conductive material from thesubstrate. Thus, both bulk and residual conductive material removal fora substrate may be performed on a single platen without lifting thesubstrate from the pad assembly 1540. Examples of other pad assemblythat may be adapted to benefit from the invention is described belowwith reference to FIGS. 15-17. It is also contemplated that other padassemblies may be utilized, including those described above and thoseincorporating windows that facilitate sensing polishing performance.

[0240] Conductive Article with Interposed Pad

[0241]FIG. 15 is a sectional view of another embodiment of a conductivearticle 1600. The conductive article 1600 generally includes aconductive portion 1602 adapted to contact a substrate during polishing,an article support portion 1604 and an interposed pad 1606 sandwichedbetween the conductive portion 1602 and the article support portion1604. The conductive portion 1602 and article support portion 1604 maybe configured similar to any of the embodiments described herein ortheir equivalent. A layer of adhesive 1608 may be provided on each sideof the interposed pad 1606 to couple the interposed pad 1606 to thearticle support portion 1604 and the conductive portion 1602. Theconductive portion 1602, the article support portion 1604 and theinterposed pad 1606 may be coupled by alternative methods therebyallowing the components of the conductive article 1600 to be easilyreplaced as a single unit after its service life, simplifyingreplacement, inventory and order management of the conductive article1600.

[0242] Optionally, the support portion 1604 may be coupled to anelectrode 204 and replaceable with the conductive article 1600 as asingle unit. The conductive article 1600, optionally including theelectrode 204, may also include a window formed therethrough as depictedand described with reference to FIG. 7F.

[0243] The interposed pad 1606 is generally harder than the articlesupport portion 1604 and is a hard or harder than the conductive portion1602. The invention contemplates the interposed pad 1606 mayalternatively be softer than the conductive portion 1602. The hardnessof the interposed pad 1606 is selected to provide stiffness to theconductive article 1600, which extends the mechanical life of both theconductive portion 1602 and the article support portion 1604 whileimproving dampening characteristics of the conductive article 1600resulting in greater global flatness of the polished substrate. In oneembodiment, the interposed pad 1606 has a hardness of less than or equalto about 80 Shore D, the article support portion 1604 has a hardness ofless than or equal to about 80 Shore A, while the conductive portion1602 has a hardness of less than or to about 100 Shore D. In anotherembodiment, the interposed pad 1606 has a thickness of less than orequal to about 35 mils, while the article support portion 1604 has athickness of less than or equal to about 100 mils.

[0244] The interposed pad 1606 may be fabricated from a dielectricmaterial that permits electrical pathways to be established through thelaminate comprising the conductive article 1600 (i.e., the stack of theconductive portion 1602, the interposed pad 1606 and the article supportportion 1604). The electrical pathways may be established as theconductive article 1600 is immersed or covered with a conductive fluid,such as an electrolyte. To facilitate the establishment of electricalpathways through the conductive article 1600, the interposed pad 1606may be at least one of permeable or perforated to allow electrolyte toflow therethrough.

[0245] In one embodiment, the interposed pad 1606 is fabricated from adielectric material compatible with the electrolyte and theelectrochemical process. Suitable materials include polymers, such aspolyurethane, polyester, mylar sheet, epoxy and polycarbonate, amongothers.

[0246] Optionally, a conductive backing 1610 may be disposed between theinterposed pad 1606 and the conductive portion 1602. The conductivebacking 1610 generally equalizes the potential across the conductiveportion 1602, thereby enhancing polishing uniformity. Having equalpotential across the polishing surface of the conductive portion 1602ensures good electrical contact between the conductive portion 1602 andconductive material being polished, particularly if the conductivematerial is residual material that is not longer a continuous film(i.e., discrete islands of film residue). Moreover, the conductivebacking 1610 provides mechanical strength to the conductive portion1602, thereby increasing the service life of the conductive article1600. Utilization of the conductive backing 1610 is beneficial inembodiments where the resistance through the conductive portion isgreater than about 500 m-ohms and enhances the mechanical integrity ofconductive portion 1602. The conductive backing 1610 may also beutilized to enhance the conductive uniformity and lower the electricalresistance of the conductive portion 1602. The conductive backing 1610may be fabricated from metal foils, metal screens, metal coated woven ornon-woven fabrics among other suitable conductive materials compatiblewith the polishing process. In one embodiment, the conductive backing1610 is compression molded to the conductive portion 1602. The backing1610 is configured not to prevent the flow of electrolyte between theconductive portions 1604 and the interposed pad 1606. The conductiveportion 1602 may be mounted onto the conductive backing 1610 throughcompression molding, lamination, injection molding and other suitablemethods.

[0247]FIG. 16 is sectional view of another embodiment of a conductivearticle 1700. The conductive article 1700 generally includes aconductive portion 1602 adapted to contact a substrate during polishing,a conductive backing 1610, an article support portion 1604 and aninterposed pad 1706 sandwiched between the conductive portion 1602 andthe article support portion 1604, having similar construction to theconductive article 1600 described above.

[0248] In the embodiment depicted in FIG. 16, the interposed pad 1706 isfabricated from a material having a plurality of cells 1708. The cells1708 are generally filled with air or other fluid, and provide aresiliency and compliance that enhances processing. The cells may beopen or closed with a size ranging from 0.1 micron meter to severalmillimeters such as between 1 micron meter to 1 millimeter. Theinvention contemplates other sizes applicable for interposed pad 1706.The interposed pad 1706 may be at least one of permeable or perforatedto allow electrolyte to flow therethrough.

[0249] The interposed pad 1706 may be fabricated from a dielectricmaterial compatible with the electrolyte and the electrochemicalprocess. Suitable materials include, but are not limited to, foamedpolymers such as foamed polyurethane and mylar sheet. The interposed pad1706 generally has a less compressibility than article support portionor sub-pad 1604 and more local deformation independence when subjectedto pressure.

[0250]FIG. 17 is sectional view of another embodiment of a conductivearticle 1800. The conductive article 1800 includes a conductive portion1802 coupled to an article support portion 1804. Optionally, theconductive article 1800 may include an interposed pad and conductivebacking (both not shown) disposed between the conductive portion 1802and the article support portion 1804.

[0251] The conductive article 1800 generally includes a plurality ofapertures 1806 formed therethrough to allow electrolyte or otherprocessing fluids to pass between an upper polishing surface 1808 of theconductive portion 1802 and a lower mounting surface 1810 of the articlesupport portion 1804. The edge 1812 defined where each of the apertures1806 intersects the upper polishing surface 1808 is contoured toeliminate any sharp corner, burrs or surface irregularities that mayscratch the substrate during processing. The contour of the edge 1812may include a radius, chamfer, taper or other configuration thatsmoothes the edge 1812 and promotes scratch minimization.

[0252] In embodiments where the conductive portion 1802 is at leastpartially fabricated from a polymer, the smoothing of the edge 1812 maybe realized by forming the aperture 1806 before the polymer hascompletely cured. Thus, the edges 1812 will become rounded as theconductive portion 1802 shrinks during the remainder of polymer curingcycle.

[0253] Additionally, or in the alternative, the edges 1812 may berounded by applying at least one of heat or pressure during or aftercuring. In one example, the edges 1812 may be burnished, heat or flametreated to round the transition between the polishing surface 1808 andthe aperture 1806 at the edge 1812.

[0254] In another example, a polymer conductive portion 1802 may becomprises of a moldable material that is repulsive to the mold or die.The repulsive nature of polymer conductive portion 1802 causes a surfacetension that causes stresses to be molded into the polymer conductiveportion 1802 that pull the material away from the mold, therebyresulting in the rounding of the edges 1812 of the apertures 1806 uponcuring.

[0255] The apertures 1806 may be formed through the conductive article1800 before or after assembly. In one embodiment, the aperture 1806includes a first hole 1814 formed in the conductive portion 1802 and asecond hole 1816 formed in the article support portion 1804. Inembodiments comprising an interposed pad, the second hole 1816 is formedtherein. Alternatively, the first hole 1814 and at least a portion ofthe second hole 1816 may be formed in the conductive portion 1802. Thefirst hole 1814 has a diameter greater than a diameter of the secondhole 1816. The smaller diameter of the second hole 1816 underlying thefirst hole 1814 provides lateral support to the conductive portion 1802surrounding the first hole 1814, thereby improving resistance to padshear and torque during polishing. Thus, the aperture 1806 comprising alarger hole at the surface 1808 disposed concentric to an underlyingsmaller hole results in less deformation of the conductive portion 1802while minimizing particle generation, thus minimizing substrate defectsincurred by pad damages.

[0256] The apertures in conductive article may be punched throughmechanical methods such as male/female punching before or after alllayers are put together. In one embodiment the conductive portion 1802compression molded onto conductive backing is first mounted ontointerposed layer, conductive portion 1802 with conductive backing andinterposed layer are mechanically perforated together, the articlesupport portion or sub-pad is mechanically perforated separately, afterperforation they are aligned together. In another embodiment all layersare put together, then perforated. The invention contemplates anyperforation techniques and sequence.

[0257]FIG. 18 is a partial sectional view of another embodiment of anECMP station 1990 and FIGS. 19A-B are side and exploded views of a ballassembly 1900 of the ECMP station 1990 of FIG. 19. The ECMP station 1990includes a platen 1950 that supports a polishing pad assembly 1960 onwhich a substrate 114 retained in a polishing head 130 is processed. Theplaten 1950 includes at least one ball assembly 1900 projectingtherefrom and coupled to a power source 1972 that are adapted to bias asurface of the substrate 114 during processing. Although two ballassemblies 1900 are shown in FIG. 18, any number of ball assemblies maybe utilized and may be distributed in any number of configurationsrelative to the centerline of the platen 1950.

[0258] The polishing pad assembly 1960 may be any pad assembly suitablefor processing the substrate, including any of the embodiments describedabove. The polishing pad assembly 1960 may include an electrode 1962 anda polishing layer 1966. In one embodiment, the polishing layer 1966 ofthe polishing pad assembly 1960 may include a polishing surface 1964that is dielectric, such as a polyurethane pad. In another embodiment,the polishing layer 1966 of the polishing pad assembly 1960 may includea polishing surface 1964 that is conductive, such as a polymer matrixhaving conductive particles dispersed therein or a conductive coatedfabric, among others. In the embodiment wherein the polishing surface1964 is conductive, the polishing surface 1964 and electrode 1962 may becoupled to the power source 1972 (shown by the dashed lines) via aswitch 1974 that allows power to be selectively switch between the ballassemblies 1900 and the conductive polishing surface 1964 torespectively facilitate bulk metal removal and residual metal removalfrom the substrate 114 without lifting the substrate 114 from thepolishing pad assembly 1960.

[0259] In one embodiment, a passage 1955 permeable to electrolyte isdisposed or formed at least through the polishing layer 1966. Thepassage 1955 allows electrolyte to establish a conductive path betweenthe substrate positioned on the polishing layer 1966 and the electrode1962. In the embodiment depicted in FIG. 18, the passage 1955 is formedthrough the polishing layer 1966. Alternatively, the passage 1955 mayextend completely through the polishing layer 1666 and the electrode1962 (as shown in phantom). In another embodiment, the passage 1955 maybe a permeable portion of the polishing layer 1966.

[0260] The ball assemblies 1900 are generally coupled to the platen 1950and extend at least partially through respective apertures 1968 formedin the polishing pad assembly 1960. Each of the ball assemblies 1900include a hollow housing 1902, an adapter 1904, a ball 1906, a contactelement 1914 and a clamp bushing 1916. The ball 1906 is movably disposedin the housing 1902, and may be disposed in a first position having atleast a portion of the ball 1906 extending above the polishing surface1964 and at least a second position where the ball 1906 is flush withthe polishing surface 1964. The ball 1906 is generally suitable forelectrically biasing the substrate 114 and may be configured asdescribed above.

[0261] The housing 1902 is fabricated from a dielectric materialcompatible with process chemistries. In one embodiment, the housing 1902is made of PEEK. The housing 1902 has a first end 1908 and a second end1910. A drive feature 1912 is formed in and/or on the first end 1908 tofacilitate installation of the ball assembly 1900 to the platen 1950.The drive feature 1912 may be holes for a spanner wrench, a slot orslots, a recessed drive feature (such as for a TORX® or hex drive, andthe like) or a projecting drive feature (such as wrench flats or a hexhead, and the like), among others. The first end 1908 additionallyincludes a seat 1926 that prevents the ball 1906 from passing out of thefirst end 1908 of the housing 1902.

[0262] The contact element 1914 is coupled between the clamp bushing1916 and adapter 1904. The contact element 1914 is generally configuredto electrically connect the adapter 1904 and ball 1906 substantially orcompletely through the range of ball positions within the housing 1902.The contact element 1914 may be configured as described above.

[0263] In the embodiment depicted in FIGS. 18-19A-B and detailed in FIG.20, the contact element 1914 includes an annular base 1942 having aplurality of flexures 1944 extending therefrom in a polar array. Theflexure 1944 includes two support elements 2102 extending from the base1942 to a distal end 2108. The support elements 2102 are coupled by aplurality of rungs 2104 to define apertures 2110 that facilitate flowpast the contact element 1916 with little pressure drop as discussedfurther below. A contact pad 2106 adapted to contact the ball 1906couples the support elements 2102 at the distal end 2108 of each flexure1944. The flexure 1944 is generally fabricated from a resilient andconductive material suitable for use with process chemistries. In oneembodiment, the flexure 1944 is fabricated from gold plated berylliumcopper.

[0264] Returning to FIGS. 17 and 18A-B, the clamp bushing 1916 includesa flared head 1924 having a threaded post 1922 extending therefrom. Theclamp busing may be fabricated from either a dielectric or conductivematerial, and in one embodiment, is fabricated from the same material asthe housing 1902. The flared head 1924 maintains the flexures 1944 at anacute angle relative to the centerline of the ball assembly 1900 so thatthe contact pads 2106 of the contact elements 1914 are positioned tospread around the surface of the ball 1906 to prevent bending, bindingand/or damage to the flexures 1944 during assembly of the ball assembly1900 and through the range of motion of the ball 1906.

[0265] The post 1922 of the clamp bushing 1916 is disposed through ahole 1946 in the base 1942 and threads into a threaded portion 1940 of apassage 1936 formed through the adapter 1904. A passage 1918 formedthrough the clamp bushing 1916 includes a drive feature 1920 at an enddisposed in the flared head 1924. Similarly, the passage 1936 includes adrive feature 1938 in an end opposite the threaded portion 1940. Thedrive features 1920, 1930 may be similar to those described above, andin one embodiment, are hexagonal holes suitable for use with a hexdriver. The clamp bushing 1924 is tightened to a level that ensures goodelectrical contact between the contact element 1914 and the adapter 1904without damaging the contact element 1914 or other component.

[0266] The adapter 1904 is generally fabricated from an electricallyconductive material compatible with process chemistries, and in oneembodiment, is fabricated from stainless steel. The adapter 1904includes an annular flange 1932 having a threaded post 1930 extendingfrom one side and a boss 1934 extending from the opposite side. Thethreaded post 1930 is adapted to mate with a contact plate 1980 disposedin the platen 1950 which couples the respective balls 1906 in the ballassemblies 1900 to the power source 1972.

[0267] The boss 1934 is received in the second end 1910 of the housing1902 and provides a surface for clamping the contact element 1914thereto. The boss 1934 additionally includes at least one threaded hole2006 disposed on the side of the boss 1934 that engages a fastener 2002disposed through a hole 2004 formed in the housing 1902, therebysecuring the housing 1902 to the adapter 1904 and capturing the ball1906 therein. In the embodiment depicted in FIG. 19A, three fastenersare shown for coupling the housing 1902 to the adapter 1904 throughcounter-sunk holes 2004. It is contemplated that the housing 1902 andadapter 1904 may be fastened by alternative methods or devices, such asstaking, adhering, bonding, press fit, dowel pins, spring pins, rivetsand retaining rings, among others.

[0268] The ball 1904 is generally actuated towards the polishing surface1906 by at least one of spring, buoyant or flow forces. In theembodiment depicted in FIG. 18, the passages 1936, 1918 formed throughthe adapter 1904 and clamp busing 1916 are coupled through the platen1950 to an electrolyte source 1970. The electrolyte source 1970 provideselectrolyte through the passages 1936 and 1918 into the interior of thehollow housing 1902. The electrolyte exits the housing 1902 between theseat 1926 and ball 1906, thus causing the ball 1906 to be biased towardthe polishing surface 1964 and into contact with the substrate 114during processing.

[0269] So that the force upon the ball 1906 is consistent across thedifferent elevations of the ball 1906 within the housing 1906, a reliefor groove 1928 is formed in the interior wall of the housing 1906 toaccept the distal ends (2108 in FIG. 20) of the flexures 1944 to preventrestricting the flow of electrolyte passing the ball 1908. An end of thegroove 1928 disposed away from the seat 1926 is generally configured tobeing at or below the diameter of the ball 1906 when the ball 1906 is inthe lowered position.

[0270] FIGS. 21-23 are perspective and sectional views of anotherembodiment of a conductive article having another embodiment of a ballassembly.

[0271]FIG. 21 is a perspective view of another embodiment of an ECMPstation 2290 and FIGS. 22-23 are perspective and partial sectional viewsof a ball assembly 2200 of the ECMP station 2290 of FIG. 21. The ECMPstation 2290 includes a platen 2250 that supports a polishing padassembly 2260 (partially shown in FIG. 22). The platen 2250 includes atleast one ball assembly 2200 projecting therefrom and coupled to a powersource 1972. The ball assembly 2200 is adapted to electrically bias asurface of the substrate 114 (shown in FIG. 23) during processing.Although one ball assembly 2200 is shown coupled to the center of theplaten 2250 in FIG. 21, any number of ball assemblies may be utilizedand may be distributed in any number of configurations relative to thecenterline of the platen 2250.

[0272] The polishing pad assembly 2260 may be any pad assembly suitablefor processing the substrate, including any of the embodiments describedabove. The polishing pad assembly 2260 may include an electrode 2462 anda polishing layer 2466. In one embodiment, the polishing layer 2466 ofthe polishing pad assembly 2260 may include a polishing surface 2464that is dielectric, such as a polyurethane pad. In another embodiment,the polishing layer 2466 of the polishing pad assembly 2260 may includea polishing surface 2464 that is conductive, such as a polymer matrixhaving conductive particles dispersed therein or a conductive coatedfabric, among others. In the embodiment wherein the polishing surface2464 is conductive, the polishing surface 2464 and electrode 2462 may becoupled to the power source 1972 (shown by the dashed lines) via aswitch 1974 that allows power to be selectively switch between the ballassembly 2200 and the conductive polishing surface 2464 to respectivelyfacilitate bulk metal removal and residual metal removal from thesubstrate 114 without lifting the substrate 114 from the polishing padassembly 2260.

[0273] In one embodiment, a permeable passage 2455 is disposed at leastthrough the polishing layer 2466 and extends at least up to theelectrode 2462. Alternatively, the passage 2455 may extend completelythrough the polishing layer 2466 and the electrode 2462 (as shown inphantom). The passage 2455 allows an electrolyte to establish aconductive path between the substrate and the electrode 2462. In oneembodiment, the passage 2455 comprises a permeable portion of thepolishing layer 2466. In another embodiment, the passage 2455 is a holeformed in the polishing layer 2466.

[0274] The ball assembly 2200 is generally coupled to the platen 2250and extends at least partially through an aperture 2468 formed in thepolishing pad assembly 2260. The ball assembly 2200 include a housing2302 that retains a plurality of balls 1906. The balls 1906 are movablydisposed in the housing 2302, and may be disposed in a first positionhaving at least a portion of the balls 1906 extending above thepolishing surface 2464 and at least a second position where the balls1906 are flush with the polishing surface 2464. The balls 1906 aregenerally suitable for electrically biasing the substrate 114 and may beconfigured as described above.

[0275] The housing 2302 is removably coupled to the platen 2250 tofacilitate replacement of the ball assembly 2200 after a number ofpolishing cycles. In one embodiment, the housing 2302 is coupled to theplaten 2250 by a plurality of screws 2308. The housing 2302 includes anupper housing 2304 coupled to a lower housing 2306 that retain the balls1906 therebtween. The upper housing 2304 is fabricated from a dielectricmaterial compatible with process chemistries. In one embodiment, theupper housing 2304 is made of PEEK. The lower housing 2306 is fabricatedfrom a conductive material compatible with process chemistries. In oneembodiment, the lower housing 2306 is made of stainless steel. The lowerhousing 2306 is coupled to the power source 1972. The housings 2304,2306 may be coupled in any number of methods, including but not limitedto, screwing, bolting, riveting, bonding, staking and clamping, amongothers. In the embodiment depicted in FIGS. 21-23, the housings 2304,2306 are coupled by a plurality of screws 2408.

[0276] The balls 1906 are disposed in a plurality of apertures 2402formed through the housings 2304, 2306. An upper portion of each of theapertures 2402 includes a seat 2404 that extends into the aperture 2402from the upper housing 2304. The seat 2404 is configured to prevent theball 1906 from exiting the top end of the aperture 2402.

[0277] A contact element 1914 is disposed in each aperture 2402 toelectrically couple the ball 1906 to the lower plate 2306. Each of thecontact element 1914 is coupled to the lower plate 2306 by a respectiveclamp bushing 1916. In one embodiment, a post 1922 of the clamp bushing1916 is threaded into a threaded portion 2410 of the aperture 2402formed through the housing 2302.

[0278] The upper portion of each of the apertures 2402 includes a reliefor groove 2406 formed in the upper housing 2304. The groove 2406 isconfigured receive the distal portions of the contact element 1914,thereby preventing restriction of electrolyte flowing between the ball1906 and housing 2302 from an electrolyte source 1970. The electrolytesource 1970 provides electrolyte through the apertures 2402 and intocontact with the substrate 114 during processing.

[0279] During processing, the balls 2204 disposed within the housing2302 are actuated towards the polishing surface 2206 by at least one ofspring, buoyant or flow forces. The balls 1906 are electrically couplethe substrate 114 to the power source 1972 through the contact elements1914 and lower plate 2306. Electrolyte, flowing through the housing 2302provides a conductive path between the electrode 2462 and biasedsubstrate 114 thereby driving an electrochemical polishing process.

[0280] Zoned Electrode

[0281] FIGS. 24A-B show bottom views of alternative embodiments of zonedelectrodes 2500A-B that may be advantageously adapted for use with thevarious embodiments of the invention described herein. The electrode2500A includes a dielectric spacer 2590 and at least two conductiveelements. The conductive elements are arranged to create a plurality ofindependently biasable zones across the surface of the electrode 2500A.In the embodiment depicted in FIG. 25A, the electrode 2500A has at leasttwo conductive elements (three conductive elements 2550, 2552, 2554 areshown by way of example in FIG. 24A) that are electrically isolated fromeach other by the spacer 2590 to create zones, an outer zone 2524, anintermediate zone 2526, and an inner zone 2528. Each zone 2524, 2526,2528, shown separated by the dashed boundary 2580, may be independentlybiasable to allow the substrate polishing profile to be tailored. Oneexample of a polishing method having zone bias control is described inthe previously incorporated U.S. patent application Ser. No. 10/244,697.

[0282] Although the zones 2524, 2526, 2528 and conductive elements 2550,2552, 2554 are shown as concentric rings, the zones may be alternativelyconfigured to suit a particular polishing application. For example, thezones 2524, 2526, 2528 and/or conductive elements 2550, 2552, 2554 maybe linear, curved, concentric, involute curves or other shapes andorientations are possible for the conductive elements. The zones 2524,2526, 2528 and/or conductive elements 2550, 2552, 2554 may be ofsubstantially equal sizes and shapes from one zone to the next, or thesizes and shapes may vary depending upon the particular zone of concern.

[0283]FIG. 24B depicts another embodiment of an electrode 2500B having aplurality of independently biasable zones. In one embodiment, theelectrode 2500B has at least n zone electrodes (shown as two electrodes2502 ₁ and 2502 _(n)), wherein n is an integer of 2 or greater. Theelectrodes 2502 ₁, 2502 _(n) each include a respective terminal 2510 a,2510 b for coupling to a power source. The electrodes 2502 ₁, 2502 _(n)generally separated by a dielectric spacer 2506 or air gap. Theelectrodes 2502 ₁, 2502 _(n) may include one or more apertures 2508 tofacilitate interfacing with one or more conductive elements, such as theball assemblies depicted in FIGS. 14C, 14C, 18 and 23.

[0284] In the embodiment depicted in FIG. 24B, the interface between atleast two adjacent electrodes in not defined at a constant distance fromthe center of the electrode 2500B. Although the gap 2506 defined at theinterface between the electrodes 2502 ₁, 2502 _(n) (illustrated in FIG.24B) has a substantially zigzag pattern, those skilled in the art willrecognize that the gap 2506 may comprise any sinuous pattern (e.g.,curves or polygons). This allows the electrodes comprising the electrode2500B to be segmented into a plurality of zones, wherein at least onezone is defined as an area having a first percentage of area covered bya conductor and at least one zone is defined a second percentage (e.g.,different than the first) of area covered by a conductor, where theconductor may be the same or separate element. Thus, n electrodes can beconfigured to provide have at least n+1 zones of control. In theembodiment depicted in FIG. 2B, the electrodes 2502 ₁ and 2502 _(n),2502 _(n+1) are configured to provide 3 zones 2504 ₁ and 2504 _(n), 2504_(n+1) of control. It is contemplated that an electrode having a singleconductive portion may be configured to provide 2 zones of control.

[0285] The first zone 2504 ₁ is defined as the area of the innerelectrode 2502 ₁ inward of the inner boundary 2580. The second zone 2504_(n) is defined as the overlapping area of the inner electrode 2502 ₁and outer electrode 2502 _(n) between the inner and outer boundaries2580. The bias over the second zone 2504 _(n) is controlled by thesynergistic effect of the biases applied independently to the innerelectrode 2502 ₁ and outer electrode 2502 _(n). The third zone 2504_(n+1) is defined as the area of the outer electrode 2502 _(n+1) outwardof the outer boundary 2580. Thus, by controlling the bias applied to thetwo individual electrodes 2502 ₁, 2502 _(n+1), the bias of the secondzone 2504 _(n+1) may be controlled separate from the bias of the firstand third zones 2504 ₁, 2504 _(n+1), thereby allowing the polishingprofile of the substrate to be tailor in-situ and/or between substrateto substrate polishes.

[0286] Thus, various embodiments of a conductive article suitable forelectrochemical polishing of substrates have been provided. Theconductive articles provide good compliance to the substrate's surfaceto promote uniform electrical contact that enhances polishingperformance. Moreover, the conductive articles are configured tominimize scratching while processing, advantageously reducing defectgeneration and thereby lowering the unit cost of processing.

[0287] While foregoing is directed to various embodiments of theinvention, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A polishing article for polishing a substrate,comprising: an upper layer having non-conductive polishing surface; aconductive layer coupled to the top layer; a first set of holes formedthrough the upper layer for exposing the conductive layer to thepolishing surface; and at least one aperture formed through the upperlayer and the conductive layer.
 2. The polishing article of claim 1,wherein the first set of holes exposes an upper surface of theconductive layer.
 3. The polishing article of claim 2, wherein the atleast one aperture is a single passage formed though the center of theupper layer and conductive layer.
 4. The polishing article of claim 2,wherein the at least one aperture further comprises a plurality ofpassages formed through the upper layer and conductive layer.
 5. Thepolishing article of claim 1 further comprising subpad sandwichedbetween the upper layer and the conductive layer.
 6. The polishingarticle of claim 5, wherein the subpad, the conductive layer and theupper layer are coupled by at least one of compression molding, staking,fastening, adhering and bonding.
 7. The polishing article of claim 5,wherein the subpad is fabricated from at least one of polyurethane,polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide(PPS), ethylene-propylene-diene-methylene (EPDM),polytetrafluoroethylene polymers, compressed felt fibers impregnatedwith urethane, and combinations thereof.
 8. The polishing article ofclaim 5, wherein the subpad has a hardness between about 20 and about 90Shore A scale.
 9. The polishing article of claim 1, wherein theconductive layer is stainless steel.
 10. The polishing article of claim1, wherein the conductive layer further comprises a plurality ofindependently biasable electrical zones.
 11. The polishing article ofclaim 10, wherein the electrical zones further comprises concentricrings.
 12. The polishing article of claim 1, wherein the conductivelayer further comprises a terminal for coupling to a power source. 13.The polishing article of claim 1, wherein the upper layer is fabricatedfrom polyurethane.
 14. A polishing article for polishing a substrate,comprising: an upper layer having non-conductive polishing surface; asubpad coupled to the upper layer opposite the polishing surface; aconductive layer sandwiching the subpad to the top layer, the conductivelayer having a terminal for coupling to a power source; a first set ofholes formed through the upper layer and subpad for exposing theconductive layer to the polishing surface; and at least one apertureformed through the upper layer, the subpad and the conductive layer. 15.The polishing article of claim 14, wherein the conductive layer furthercomprises a plurality of independently biasable electrical zones. 16.The polishing article of claim 15, wherein the conductive layer furthercomprises: a first conductive element; and a second conductive elementhaving an inner edge interleaved with an outer edge of the firstconductive element.
 17. A polishing article for polishing a substrate,comprising: an upper layer having non-conductive polishing surface; aconductive layer coupled to the top layer having a first zone and atleast a second zone, wherein a percentage of conductive material topsurface area per zone top surface area is different between the firstand second zones; a first set of holes formed through the upper layerfor exposing the conductive layer to the polishing surface; and at leastone aperture formed through the upper layer and the conductive layer.18. The polishing article of claim 17, wherein the conductive layerfurther comprises: a first conductive element; and a second conductiveelement having an inner edge interleaved with an outer edge of the firstconductive element.
 19. The polishing article of claim 17 furthercomprising a third zone, wherein the first zone comprises a firstportion of a first conductive element, the second zone comprises asecond portion of the first conductive element and a first portion of asecond conductive element and the third zone comprises a second portionof the second conductive element.
 20. The polishing article of claim 17,wherein the conductive layer further comprises: a first conductiveelement; a second conductive element circumscribing the first conductiveelement; and a third conductive element circumscribing the secondconductive element.
 21. The polishing article of claim 17, wherein theconductive layer is comprises of a magnetically coupleable material.